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Contents of Student Resources Skills Review Handbook pages 975–1009 Operations with Positive and Negative Numbers Perimeter and Area 991 975 Circumference and Area of a Circle 992 Fractions, Decimals, and Percents 976 Surface Area and Volume 993 Calculating with Percents 977 Angle Relationships 994 Factors and Multiples 978 Triangle Relationships 995 Ratios and Proportions 980 Congruent and Similar Figures 996 Converting Units of Measurements 981 More Problem Solving Strategies 998 Scientific Notation 982 Logical Argument 1000 Significant Digits 983 Writing Algebraic Expressions 984 Conditional Statements and Counterexamples 1002 Binomial Products 985 Venn Diagrams 1004 LCDs of Rational Expressions 986 Mean, Median, Mode, and Range 1005 The Coordinate Plane 987 Graphing Statistical Data 1006 Transformations 988 Organizing Statistical Data 1008 Line Symmetry 990 Extra Practice for Chapters 1–14 pages 1010–1023 Tables pages 1024–1034 Symbols Measures Formulas Properties 1024 1025 1026 1033 English-Spanish Glossary pages 1035 1035– –1084 Index pages 1085 1085– –1104 Credits pages 1105 1105– –1106 Worked-Out Solutions Selected Answers 974 page WS1 page SA1 Student Resources n2pe-9010.indd Sec1:974 10/11/05 12:50:25 PM Sk ills Re Rev v iew Handboo Handbook k To add positive and negative numbers, you can use a number line. To subtract any number, add its opposite. EXAMPLE To add a positive number, move to the right. To add a negative number, move to the left. 26 25 24 22 0 21 1 2 3 4 5 6 Add or subtract. a. 1 1 (25) End 23 SKILLS REVIEW HANDBOOK Operations with Positive and Negative Numbers b. 22 2 (25) 5 22 1 5 Move 5 units to the left. 25 24 23 22 21 0 Start Start 1 Move 5 units to the right. 23 22 21 2 c 1 1 (25) 5 24 The opposite of 25 is 5. 0 1 2 End 3 4 c 22 2 (25) 5 3 To multiply or divide positive and negative numbers, use the following rules. • The product or quotient of two numbers with the same sign is positive. • The product or quotient of two numbers with different signs is negative. EXAMPLE Multiply or divide. a. 3 p 7 5 21 b. 23(27) 5 21 c. 18 4 2 5 9 d. 218 4 (22) 5 9 e. 23(7) 5 221 f. 3(27) 5 221 g. 218 4 2 5 29 h. 18 4 (22) 5 29 PRACTICE Perform the indicated operation. 1. 2 1 (28) 2. 5 2 12 3. 26(10) 4. 230 4 (22) 6. 7(25) 7. 18 2 10 8. 27 1 (212) 9. 11(4) 5. 24 1 6 10. 81 4 (29) 11. 212 4 3 12. 29(28) 13. 21 1 13 14. 45 4 (29) 15. 26(12) 16. 14 2 (29) 17. 232 4 16 18. 223 1 (25) 19. 28 2 (25) 20. 17 2 (218) 21. 29(21) 22. 23 2 (211) 23. 218 4 (23) 24. 14 1 (27) 25. 5(23) 26. 21 1 (28) 27. 22 2 10 28. 29 1 26 29. 220 4 (24) 30. 22 4 (22) 31. 27(26) 32. 1 2 24 33. 215 2 2 34. 0 1 (24) 35. 16 4 8 Skills Review Handbook n2pe-9020.indd 975 975 11/21/05 10:26:41 AM SKILLS REVIEW HANDBOOK Fractions, Decimals, and Percents A percent is a ratio with a denominator of 100. The word percent means “per hundred,” or “out of one hundred.” The symbol for percent is %. In the model at the right, 71 of the 100 squares are shaded. You can write the shaded part of the model as a fraction, a decimal, or a percent. 71 Fraction: seventy-one divided by one hundred, or }} 100 Decimal: seventy-one hundredths, or 0.71 Percent: seventy-one percent, or 71% EXAMPLE Write as a fraction. 94 5 47 a. 94% 5 }} }} 100 50 EXAMPLE 3 c. 0.3 5 three tenths 5 }} 10 Write as a decimal. 15 5 0.15 a. 15% 5 }} 100 EXAMPLE 20 5 1 b. 20% 5 }} } 5 100 106 5 1.06 b. 106% 5 }} 100 5 5 5 4 8 5 0.625 c. } 8 Write as a percent. 41 5 41% a. 0.41 5 }} 100 8 5 80 5 80% b. 0.8 5 }} }} 10 100 5 5 5 p 25 5 125 5 125% c. } }}} }} 4 4 p 25 100 PRACTICE Write as a fraction. 1. 0.65 2. 0.08 3. 1.5 4. 0.13 5. 0.7 6. 50% 7. 26% 8. 3% 9. 95% 10. 110% Write as a decimal. 1 11. } 4 9 12. } 10 30 13. } 25 2 14. } 5 3 15. } 8 16. 16% 17. 142% 18. 1% 19. 30% 20. 6.5% 21. 0.6 22. 0.24 23. 1.3 24. 0.07 25. 0.45 1 26. } 10 4 27. } 5 17 28. } 20 5 29. } 2 3 30. } 16 Write as a percent. 976 n2pe-9020.indd 976 Student Resources 11/21/05 10:26:45 AM Calculating with Percents EXAMPLE Word what of is n 3 5 Symbol Answer the question. a. What is 15% of 20? b. What percent of 8 is 6? n 5 0.15 3 20 n53 c. 80% of what number is 4? n3856 0.8 3 n 5 4 n 5 6 4 8 5 0.75 5 75% 3 is 15% of 20. n 5 4 4 0.8 5 5 75% of 8 is 6. SKILLS REVIEW HANDBOOK You can use equations to calculate with percents. Replace words with symbols as shown in the table at the right. Below are three types of questions you can answer with percents. 80% of 5 is 4. Amount of increase or decrease . To find a percent of change, calculate }}}}}}}}}}}}}} Original amount EXAMPLE Find the percent of change. a. A class increases from 21 students to 25 students. 25 2 21 4 }}}} 5 }} ø 0.19 5 19% increase 21 21 b. A price decreases from $12 to $9. 12 2 9 3 }}} 5 }} 5 0.25 5 25% decrease 12 12 PRACTICE Answer the question. 1. What is 98% of 200? 2. What is 25% of 8? 3. What is 30% of 128? 4. What is 5% of 700? 5. What is 100% of 17? 6. What is 150% of 14? 7. What is 0.2% of 500? 8. What is 6.5% of 3000? 9. What percent of 100 is 54? 10. What percent of 18 is 9? 11. What percent of 80 is 8? 12. What percent of 15 is 20? 13. What percent of 30 is 6? 14. What percent of 5 is 8? 15. What percent of 50 is 1? 16. 50% of what number is 6? 17. 55% of what number is 44? 18. 10% of what number is 6? 19. 75% of what number is 45? 20. 1% of what number is 2? 21. 90% of what number is 63? 22. 12% of what number is 60? 23. 200% of what number is 16? Find the percent of change. Round to the nearest percent if necessary. 24. A class increases from 20 to 28 students. 25. Time decreases from 60 to 45 minutes. 26. A price is reduced from $200 to $180. 27. Votes increase from 200 to 300. 28. A test is shortened from 40 to 32 items. 29. Membership increases from 820 to 1605. 30. A wage rises from $8.75 to $10.00. 31. The temperature drops from 248F to 58F. Skills Review Handbook n2pe-9020.indd 977 977 11/21/05 10:26:46 AM SKILLS REVIEW HANDBOOK Factors and Multiples Factors are numbers or expressions that are multiplied together. A prime number is a whole number greater than 1 that has exactly two whole number factors, 1 and itself. The table shows all the prime numbers less than 100. A composite number is a whole number greater than 1 that has more than two whole number factors. Prime Numbers Less Than 100 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 When you write a composite number as a product of prime numbers, you are writing its prime factorization. EXAMPLE Write the prime factorization of 60. Use a factor tree. Write 60 at the top. Then draw two branches and write 60 as the product of two factors. Continue to draw branches until all the factors are prime numbers. Two factor trees for 60 are given at the right. Both show 60 5 2 p 2 p 3 p 5. 60 60 2 p 30 3 p 20 2 p 15 2 c The prime factorization of 60 is 2 p 3 p 5. 3 p 5 4 p 5 2 p 2 A whole number that is a factor of two or more nonzero whole numbers is a common factor of the numbers. The largest of the common factors is the greatest common factor (GCF). EXAMPLE Find the greatest common factor (GCF) of 18 and 45. Method 1 List factors. Method 2 Use prime factorization. Factors of 18: 1, 2, 3, 6, 9, 18 Prime factorization of 18: 2 p 3 p 3 Factors of 45: 1, 3, 5, 9, 15, 45 Prime factorization of 45: 3 p 3 p 5 The GCF is 9, the greatest of the common factors. The GCF is the product of the common prime factors: 3 p 3 5 9. A multiple of a whole number is the product of the number and any nonzero whole number. A common multiple of two or more numbers is a multiple of all of the numbers. The least common multiple (LCM) is the smallest of the common multiples. EXAMPLE 978 n2pe-9020.indd 978 Find the least common multiple (LCM) of 12 and 15. Method 1 List multiples. Method 2 Use prime factorization. Multiples of 12: 12, 24, 36, 48, 60, . . . Prime factorization of 12: 22 p 3 Multiples of 15: 15, 30, 45, 60, . . . Prime factorization of 15: 3 p 5 The LCM is 60, the least of the common multiples. Form the LCM of the numbers by writing each prime factor to the highest power it occurs in either number: 22 p 3 p 5 5 60. Student Resources 11/21/05 10:26:48 AM EXAMPLE 3 10 SKILLS REVIEW HANDBOOK The least common denominator (LCD) of two fractions is the least common multiple of the denominators. Use the LCD to add or subtract fractions with different denominators. 5 8 Add: }} 1 } The least common multiple of the denominators, 10 and 8, is 40. So, the least common denominator (LCD) of the fractions is 40. 3 5 3 p 4 5 12 and 5 5 5 p 5 5 25 Rewrite the fractions using the LCD of 40: }} }}} }} } }}} }} 10 10 p 4 40 8 8p5 40 3 1 5 5 12 1 25 5 37 Add the numerators and keep the same denominator: }} } }} }} }} 10 8 40 40 40 PRACTICE Write the prime factorization of the number. If the number is prime, write prime. 1. 42 2. 104 3. 75 4. 23 5. 70 6. 27 7. 72 8. 180 9. 47 10. 100 11. 88 12. 49 14. 142 15. 32 13. 83 Find the greatest common factor (GCF) of the numbers. 16. 4, 6 17. 24, 40 18. 10, 25 19. 55, 44 20. 28, 35 21. 8, 20 22. 5, 8 23. 15, 12 24. 16, 32 25. 70, 90 26. 2, 18 27. 9, 21 28. 36, 42, 54 29. 7, 12, 17 30. 45, 63, 81 Find the least common multiple (LCM) of the numbers. 31. 4, 16 32. 2, 14 33. 5, 6 34. 16, 24 35. 6, 8 36. 12, 20 37. 3, 6 38. 18, 8 39. 9, 12 40. 9, 5 41. 10, 15 42. 7, 9 43. 40, 4, 5 44. 25, 30, 3 45. 27, 81, 33 Perform the indicated operation(s). Simplify the result. 113 46. } } 2 8 32 5 47. } }} 4 16 7 23 48. }} } 5 10 111 49. } } 2 3 5 11 50. }} } 3 12 411 51. } } 5 8 1 13 52. }} } 4 10 521 53. } } 6 2 7 2 11 54. } }} 8 16 9 21 55. }} } 3 10 221 56. } } 3 6 2 1 1} 57. } 5 4 41 1 25 58. } }} } 5 12 6 32 3 23 59. } }} } 4 2 10 9 2121 60. }} } } 5 10 2 71 3 21 61. } }} } 4 16 8 8122 7 62. } } }} 9 3 12 4 11 1 1 }} 63. } } 15 3 6 11211 64. } } } 4 2 3 15 2 7 1 1 65. }} }} } 16 10 2 5 211 7 66. }} } }} 24 6 12 321 1 1} 67. } } 5 4 2 5232 2 68. } } }} 5 6 15 4132 7 69. } } }} 4 9 12 Skills Review Handbook n2pe-9020.indd 979 979 11/21/05 10:26:48 AM SKILLS REVIEW HANDBOOK Ratios and Proportions A ratio uses division to compare two quantities. Three Ways to Write the Ratio of a to b You can write a ratio of two quantities a and b, where b is not equal to 0, in three ways. a to b a b a:b } You should write ratios in simplest form. EXAMPLE Write the ratio of 12 boys to 16 girls in three ways. Boys Girls 12 5 12 4 4 5 3 First write the ratio as a fraction in simplest form: }}} 5 }} }}} } 16 16 4 4 4 3. c Three ways to write the ratio of boys to girls are 3 to 4, 3 : 4, and } 4 A proportion is an equation stating that two ratios are equal. You can use cross multiplication to solve a proportion. EXAMPLE 9 a b c d b. }} 5 } If } 5 }, where b ? 0 and d ? 0, then ad 5 bc. Solve the proportion. n 54 5 } 5 }} a. Using Cross Multiplication to Solve Proportions 5 p 54 5 9 p n 270 5 9n 30 5 n Cross multiply. Simplify. Solve for n. x 40 3 8 x p 8 5 40 p 3 8x 5 120 x 5 15 Cross multiply. Simplify. Solve for x. PRACTICE Write the ratio in simplest form. Express the answer in three ways. 1. 3 to 9 2. 16 to 24 3. 10 to 8 4. 6 to 2 5. 25 to 30 6. 60 to 10 7. 4 to 4 8. 8 to 20 9. 32 to 72 10. 42 to 15 11. 14 to 2 12. 12 to 15 x 5 12 13. }} }} 14 24 8 5 d 14. }} }} 24 36 15 5 3 15. }} } 4 n 9 5 5 16. }} } 45 h a5 4 17. } }} 6 12 13 5 91 18. }} }} t 7 75 5 r 19. }} } 120 8 b 52 20. }} } 90 3 4 5 n 21. }} }} 11 110 5 5 150 22. } }} 90 z 95x 23. } } 8 6 72 5 24 24. }} }} 105 m 17 5 51 25. }} }} 33 a 20 5 24 26. }} }} 125 n 16 5 8 27. }} } 144 x 96 5 t 28. }} } 6 3 Solve the proportion. 980 n2pe-9020.indd 980 Student Resources 11/21/05 10:26:50 AM Converting Units of Measurement SKILLS REVIEW HANDBOOK The table of measures on page 1025 gives many statements of equivalent measures. Using each statement, you can write two different conversion factors. Statement of Equivalent Measures Conversion Factors 100 cm 5 1 m }}}} 5 1 and }}}} 5 1 100 cm 1m 1m 100 cm To convert from one unit of measurement to another, multiply by a conversion factor. Use the one that will eliminate the starting unit and keep the desired unit. EXAMPLE Copy and complete. a. 3.5 m 5 ? cm b. 620 cm 5 ? m 100 cm 5 (3.5 3 100) cm 5 350 cm 3.5 m 3 }}}} 1 m 5 620 m 5 6.2 m 620 cm 3 }}}} }} c So, 3.5 m 5 350 cm. c So, 620 cm 5 6.2 m. 1m 100 cm 100 Sometimes you need to use more than one conversion factor. EXAMPLE Copy and complete: 7 days 5 ? sec Find the appropriate statements of equivalent measures. 24 h 5 1 day, 60 min 5 1 h, and 60 sec 5 1 min 24 h , 60 min , and 60 sec Write conversion factors: }}} }}}} }}} 1 day 1h 1 min Multiply by conversion factors to eliminate days and keep seconds. 24 h 3 60 min 3 60 sec 5 (7 3 24 3 60 3 60) sec 5 604,800 sec 7 days 3 }}} }}}} }}} 1 day 1 min 1h c So, 7 days 5 604,800 sec. PRACTICE Copy and complete. 1. 6 L 5 ? mL 2. 2 mi 5 ? ft 3. 80 oz 5 ? lb 4. 4 days 5 ? h 5. 77 mm 5 ? cm 6. 5 gal 5 ? qt 7. 48 ft 5 ? yd 8. 1500 mL 5 ? L 10. 125 lb 5 ? oz 11. 800 g 5 ? kg 12. 900 sec 5 ? min 13. 72 in. 5 ? ft 14. 2.5 ton 5 ? lb 15. 90 min 5 ? h 16. 65,000 mg 5 ? g 17. 100 yd 5 ? in. 18. 3.5 kg 5 ? g 19. 6 pt 5 ? qt 20. 1 week 5 ? min 21. 2 oz 5 ? lb 22. 1 km 5 ? mm 23. 1 mi 5 ? in. 24. 5 gal 5 ? c 25. 288 in.2 5 ? ft 2 26. 24 pt 5 ? gal 27. 4 kg 5 ? g 28. 7 hr 5 ? sec 9. 40 m 5 ? cm Skills Review Handbook n2pe-9020.indd 981 981 11/21/05 10:26:52 AM SKILLS REVIEW HANDBOOK Scientific Notation Scientific notation is a way to write numbers using powers of 10. A number is written in scientific notation if it has the form c 3 10n where 1 ≤ c < 10 and n is an integer. The table shows some powers of ten in order from least to greatest. Power of Ten 1023 1022 1021 100 101 102 103 Value 0.001 0.01 0.1 1 10 100 1000 EXAMPLE a. 12,800,000 Write the number in scientific notation. Standard form b. 0.0000039 Standard form 12,800,000 Move the decimal point 7 places to the left. 0.0000039 Move the decimal point 6 places to the right. 1.28 3 107 Use 7 as an exponent of 10. 3.9 3 1026 Use 26 as an exponent of 10. EXAMPLE a. 6.1 3 104 Write the number in standard form. Scientific notation b. 5.74 3 1025 Scientific notation 6.1 3 104 The exponent of 10 is 4. 5.74 3 1025 The exponent of 10 is 25. 61,000 Move the decimal point 4 places to the right. 0.0000574 Move the decimal point 5 places to the left. 61,000 Standard form 0.0000574 Standard form PRACTICE Write the number in scientific notation. 1. 0.6 2. 25,000,000 3. 0.08 4. 0.00542 5. 40.8 6. 7 7. 0.000385 8. 8,145,000 9. 41,236 10. 0.0000016 11. 486,000 12. 0.000000009 13. 0.01002 14. 1,000,000,000 15. 7050.5 16. 0.37 17. 9850 18. 0.0000206 19. 805 20. 0.0005 Write the number in standard form. 982 n2pe-9020.indd 982 21. 5 3 103 22. 4 3 1022 23. 8.2 3 1021 24. 6.93 3 102 25. 3.2 3 1023 26. 9.01 3 1025 27. 7.345 3 105 28. 2.38 3 1022 29. 1.814 3 100 30. 2.7 3 108 31. 1 3 106 32. 4.9 3 1024 33. 8 3 1026 34. 5.6 3 104 35. 1.87 3 109 36. 7 3 1024 37. 6.08 3 106 38. 9.009 3 1023 39. 3.401 3 107 40. 5.32 3 101 Student Resources 11/21/05 10:26:53 AM Significant Digits SKILLS REVIEW HANDBOOK Significant digits indicate how precisely a number is known. Use the following guidelines to determine the number of significant digits. • All nonzero digits are significant. • All zeros that appear between two nonzero digits are significant. • For a decimal, all zeros that appear after the last nonzero digit are significant. For a whole number, you cannot tell whether any zeros after the last nonzero digit are significant, so you should assume that they are not significant. Sometimes calculations involve measurements that have various numbers of significant digits. In this case, a general rule is to carry all digits through the calculation and then round the result to the same number of significant digits as the measurement with the fewest significant digits. When you calculate with units that cannot be divided into fractional parts, such as number of people, consider only the significant digits of the other number(s). EXAMPLE a. 12.6 3 0.05 0.63 0.6 Perform the calculation. Write your answer with the appropriate number of significant digits. 3 significant digits 1 significant digit b. 840 2 significant digits 1 702 3 significant digits The product has 2 significant digits. 1542 The sum has 4 significant digits. Round to 1 significant digit. 1500 Round to 2 significant digits. c. $61.20 restaurant bill 4 6 people The number of people is exact, so consider only the 4 significant digits of the bill, $61.20. The answer should have 4 significant digits. $61.20 4 6 5 $10.20 c Each person pays $10.20. PRACTICE Perform the calculation. Write your answer with the appropriate number of significant digits. 1. 600 1 30 2. 5 2 2.6 3. 12 p 6.75 4. 0.098 1 0.14 1 0.369 5. 3.6053 2 1.720 6. 40 4 3.5 7. 8.0 2 3.1 8. 31.7 p 6.8 p 0.435 9. 30.5 p 6.40 13. 4016 2 3007 10. 3.18 1 2.0005 11. 0.088 4 2.44 12. 8650 1 380 2 49 14. 1.35 1 14.8 15. 320 4 18 16. 38.1 p 3.04 4 0.024 17. $1.45 per notebook p 12 notebooks 18. 10.0 liters of water 2 4.5 liters of water 19. 260 pints of milk 4 106 students 20. 0.5 yard of fabric 1 0.87 yard of fabric 21. 27,973 books 4 11 libraries 22. 12.76 gallons of gas 1 6.08 gallons of gas 23. $6.95 per ticket p 180 tickets 24. 1540 pounds 2 160 pounds 2 85 pounds Skills Review Handbook n2pe-9020.indd 983 983 11/21/05 10:26:54 AM SKILLS REVIEW HANDBOOK Writing Algebraic Expressions To solve a problem using algebra, you often need to write a phrase as an algebraic expression. EXAMPLE Write the phrase as an algebraic expression. a. 6 less than a number b. The cube of a number c. Double a number “Less than” indicates subtraction. “Cube” indicates raising to the third power. “Double” indicates multiplication by 2. cn26 c n3 c 2n EXAMPLE Write an algebraic expression to answer the question. a. Rebecca walks three times as far to school as Meghan does. If Meghan walks m blocks to school, how many blocks to school does Rebecca walk? c 3m b. Kate is 8 inches taller than Noah. If Noah is n inches tall, how tall is Kate? cn18 PRACTICE Write the phrase as an algebraic expression. 1. 8 more than a number 2. 10 times a number 3. Twice a number 4. 6 less than a number 5. One fifth of a number 6. 4 greater than a number 7. 5 times a number 8. A number squared 9. 25% of a number 10. Half a number 11. 2 less than a number 12. The square root of a number Write an algebraic expression to answer the question. 13. Allison is 4 years younger than her sister Camille. If Camille is c years old, how old is Allison? 14. Ryan bought a movie ticket for x dollars. He paid with a $20 bill. How much change should Ryan get? 15. Bridget spent $5 more than Tom spent at the mall. If Tom spent x dollars, how much did Bridget spend? 16. Marc has twice as many baseball cards as hockey cards. If Marc has h hockey cards, how many baseball cards does he have? 17. Elizabeth’s ballet class is 45 minutes long. If Elizabeth is m minutes late for ballet class, how many minutes will she spend in class? 18. Steve drove x miles per hour for 5 hours. How many miles did Steve drive? 19. Wendy bought 10 pens priced at x dollars each. How much did she spend? 984 n2pe-9020.indd 984 Student Resources 11/21/05 10:26:55 AM Binomial Products EXAMPLE Simplify (2x 1 1)(x 1 3). Draw a rectangle with dimensions 2x 1 1 and x 1 3. Use the dimensions to divide the rectangle into parts. Then find the area of each part. The binomial product (2x 1 1)(x 1 3) is the sum of the areas of all the parts. 2 There are 2 blue parts with area x , 7 green parts with area x, and 3 yellow parts with area 1. x 2x 1 1 x 1 x x2 x2 x 1 1 1 x x x x x x 1 1 1 x13 (2x 1 1)(x 1 3) 5 2x2 1 7x 1 3 SKILLS REVIEW HANDBOOK A monomial is a number, a variable, or the product of a number and one or more variables. A binomial is the sum of two monomials. In other words, a binomial is a polynomial with two terms. You can use a geometric model to find the product of two binomials. Another way to find the product of two binomials is to use the distributive property systematically. Multiply the first terms, the outer terms, the inner terms, and the last terms of the binomials. This is called FOIL for the words First, Outer, Inner, and Last. EXAMPLE Simplify (x 1 2)(4x 2 5). First Outer Inner Last (x 1 2)(4x 2 5) 5 x(4x) 1 x(25) 1 2(4x) 1 2(25) 2 Use FOIL. 5 4x 2 5x 1 8x 2 10 Multiply. 5 4x2 1 3x 2 10 Combine like terms. PRACTICE Simplify. 1. (a 1 5)(a 1 3) 2. (m 1 4)(m 1 11) 3. (t 1 8)(t 1 7) 4. (z 1 1)(z 1 6) 5. (y 1 4)(y 1 2) 6. (x 1 9)(x 1 9) 7. (y 2 2) 2 8. (n 1 6) 2 9. (4 2 z)2 10. (a 1 10)(a 2 10) 11. (y 1 3)(y 2 7) 12. (k 1 1)2 13. (5x 2 4)(5x 1 4) 14. (3 1 n)2 15. (c 1 5)(2c 2 7) 16. (a 1 5)(a 1 5) 17. (7 2 z)(7 1 z) 18. (3x 2 8)(x 2 6) 20. (3 2 g)(2g 1 3) 21. (4 2 x)(8 1 x) 22. (3n 2 1)(n 2 4) 23. (2a 1 9)(a 2 9) 24. (8x 1 1)(x 1 1) 25. (5x 1 2)(2x 2 5) 26. (2d 2 5)(3d 2 1) 27. (24z 1 3)(6z 2 1) 19. (4a 1 3) 2 Skills Review Handbook n2pe-9020.indd 985 985 11/21/05 10:26:56 AM SKILLS REVIEW HANDBOOK LCDs of Rational Expressions A rational expression is a fraction whose numerator and denominator are nonzero polynomials. The least common denominator (LCD) of two rational expressions is the least common multiple of the denominators. To find the LCD, follow these three steps: STEP 1 Write each denominator as the product of its factors. STEP 2 Write the product consisting of the highest power of each factor that appears in either denominator. STEP 3 Simplify the product from Step 2 to write the LCD. EXAMPLE Find the least common denominator of the rational expressions. 3 and 1 b. }} }} 12x 8x 2 2 and 2 a. }} }}3 5xy y STEP 1 Factors: Factors: 5xy 5 5 p x p y 8x2 5 23 p x2 3 y 5y 3 Factors: 2 STEP 2 Product: 5 p x p y 3 STEP 3 LCD: 5xy x 21 and c. }}} }}}}}} 3x 1 6 x2 2 3x 2 10 3 3x 1 6 5 3 p (x 1 2) 2 12x 5 2 p 3 p x x 2 3x 2 10 5 (x 1 2) p (x 2 5) Product: 23 p 3 p x2 Product: 3 p (x 1 2) p (x 2 5) LCD: 24x 2 LCD: 3(x 1 2)(x 2 5) PRACTICE Find the least common denominator of the rational expressions. 986 n2pe-9020.indd 986 1 and 4 1. }} }} 2ab a2 5 and 6 2. }} }} 6k 2 7k 2 2 and 2 3. }} }} z3 z2 4 and 23 4. }} }} 5x 10x m and 1 5. }} }}} 14 18m 19 and 3 6. }}} }}} 20xy 16xy 1 and 1 7. }} }} 3y 3y 2 24 and 2 8. }}} }}} 9ab2 21a2b n and n2 9. }}} }}} n12 n22 21 and 3 10. }}} }}} x21 x13 28 and 4 11. }}} }}} 5n 1 5 n11 y 1 12. } and }}} 8 2y 1 8 1 2 13. }}}} and }}}} 2m 2 6 3m 2 9 a and 2a 14. }} }}}} n2 n2 2 6n 1 and 1 15. }}} }}}} x24 (x 2 4)2 3 4 16. }}}} and }}}} 4x 1 12 6x 1 18 29 1 and 17. }} }}}}} 2n3 10n2 1 8n 10 17b 18. }}}} and }}}} 15b 2 30 9b 2 18 25 and 3 19. }}}} }}}} (k 1 3)4 (k 1 3)2 8 1 and 20. }}} }}}} y25 3y 2 15 n2 n 21. }}}}} and }}}} 10n 1 20 7n 1 14 20 1 22. }}}} and }}}} 5z 2 40 9z 2 56 2a 2 23. }}}}}} and }}} a12 a2 1 4a 1 4 1 21 24. }}} and }}}}} 2z 2 6 z2 2 z 2 6 3k and 2k 25. }}} }}}}}} k23 k 2 2 5k 1 6 x 2x 26. }}} and }}}}}} x2 2 9 x 2 1 3x 2 18 m2 25 27. }}}}}}} and }}}}}}} 2 m 2 11m 1 28 m2 1 5m 2 45 Student Resources 11/21/05 10:26:58 AM The Coordinate Plane Each point in a coordinate plane is represented by an ordered pair. The first number is the x-coordinate, and the second number is the y-coordinate. The ordered pair (3, 1) is graphed at the right. The x-coordinate is 3, and the y-coordinate is 1. So, the point is right 3 units and up 1 unit from the origin. EXAMPLE y-axis Quadrant II 4 (2, 1) 3 origin 2 (0, 0) y Quadrant I (1, 1) (3, 1) 1 2 3 4 5 6x 262524232221 21 22 23 (2, 2) Quadrant III 24 x-axis (1, 2) Quadrant IV SKILLS REVIEW HANDBOOK A coordinate plane is formed by the intersection of a horizontal number line called the x-axis and a vertical number line called the y-axis. The axes meet at a point called the origin and divide the coordinate plane into four quadrants, numbered I, II, III, and IV. Graph the points A(2, 21) and B(24, 0) in a coordinate plane. A(2, 21) Start at the origin. The x-coordinate is 2, so move right 2 units. The y-coordinate is 21, so move down 1 unit. Draw a point at (2, 21) and label it A. B(24, 0) Start at the origin. The x-coordinate is 24, so move left 4 units. The y-coordinate is 0, so move up 0 units. Draw a point at (24, 0) and label it B. 4 3 2 1 B(24, 0) y 3 4 5 6x 1 262524232221 21 22 23 24 A(2, 21) PRACTICE Graph the points in a coordinate plane. 1. A(7, 2) 2. B(6, 27) 3. C(2, 23) 4. D(28, 0) 5. E(24, 28) 6. F(1, 3) 7. G(3, 0) 8. H(1, 25) 9. I(0, 22) 10. J(26, 5) 11. K(5, 8) 12. L(8, 22) 13. M(23, 24) 14. N(27, 8) 15. P(25, 1) 16. Q(22, 26) 17. R(0, 6) 18. S(24, 21) 19. T(4, 4) 20. V(23, 7) Give the coordinates and the quadrant or axis of the point. 21. A 24. D 22. B 25. E 23. C 5 26. F 27. G 28. H 29. J 30. K 31. L 32. M 33. N 34. O 35. P 36. Q 37. R 38. S 39. T 40. U 41. V 42. W 43. X 44. Y T 4 F 3 N 2 1 D y A M G S W U E L 26 24 22 O R V H 3 4 5 6x 1 K J B23 X Œ 24 Y P C Skills Review Handbook n2pe-9020.indd 987 987 11/21/05 10:26:59 AM SKILLS REVIEW HANDBOOK Transformations A transformation is a change made to the position or to the size of a figure. Each point (x, y) of the figure is mapped to a new point, and the new figure is called an image. A translation is a transformation in which each point of a figure moves the same distance in the same direction. A figure and its translated image are congruent. EXAMPLE Translation a Units Horizontally and b Units Vertically (x, y) → (x 1 a, y 1 b) Translate } FG right 3 units and down 1 unit. y 13 F 21 F9 To move right 3 units, use a 5 3. To move down 1 unit, use b 5 21. So, use (x, y) → (x 1 3, y 1 (21)) with each endpoint. 1 F(2, 4) → F9(2 1 3, 4 1 (21)) 5 F9(5, 3) G(1, 1) → G9(1 1 3, 1 1 (21)) 5 G9(4, 0) G G9 1 x Graph the endpoints (5, 3) and (4, 0). Then draw the image. A reflection is a transformation in which a figure is reflected, or flipped, in a line, called the line of reflection. A figure and its reflected image are congruent. EXAMPLE Reflection in x-axis Reflection in y-axis (x, y) → (x, 2y) (x, y) → (2x, y) Reflect n ABC in the y-axis. y A9 A B9 B Use (x, y) → (2x, y) with each vertex. A(4, 3) → A9(24, 3) B(1, 2) → B9(21, 2) C(3, 1) → C9(23, 1) 1 C9 Change each x-coordinate to its opposite. C x 1 Graph the new vertices. Then draw the image. A rotation is a transformation in which a figure is turned about a fixed point, called the center of rotation. The direction can be clockwise or counterclockwise. A figure and its rotated image are congruent. EXAMPLE Rotation About the Origin 1808 either direction (x, y) → (2x, 2y) 908 clockwise (x, y) → (y, 2x) 908 counterclockwise (x, y) → (2y, x) Rotate RSTV 1808 about the origin. y R(2, 2) → R9(22, 22) S(4, 2) → S9(24, 22) T(4, 1) → T9(24, 21) V(1, 0) → V9(21, 0) Change every coordinate to its opposite. R 2 Use (x, y) → (2x, 2y) with each vertex. S V9 S9 T V T9 2 x R9 Graph the new vertices. Then draw the image. 988 n2pe-9020.indd 988 Student Resources 11/21/05 10:27:01 AM EXAMPLE Dilation with Scale Factor k with Respect to the Origin SKILLS REVIEW HANDBOOK A dilation is a transformation in which a figure stretches or shrinks depending on the dilation’s scale factor. A figure stretches if k > 1 and shrinks if 0 < k < 1. A figure and its dilated image are similar. (x, y) → (kx, ky) Dilate JKLM using a scale factor of 0.5. The scale factor is k 5 0.5, so multiply every coordinate by 0.5. Use (x, y) → (0.5x, 0.5y) with each vertex. J(4, 4) → J9(0.5 p 4, 0.5 p 4) 5 J9(2, 2) K(6, 4) → K9(0.5 p 6, 0.5 p 4) 5 K9(3, 2) L(6, 21) → L9(0.5 p 6, 0.5 p (21)) 5 L9(3, 20.5) M(4, 21) → M9(0.5 p 4, 0.5 p (21)) 5 M9(2, 20.5) y J J9 K K9 1 M9 L9 5 M x L Graph the new vertices. Then draw the image. PRACTICE Find the coordinates of N(23, 8) after the given transformation. For rotations, rotate about the origin. 1. Rotate 1808. 2. Reflect in x-axis. 3. Translate up 3 units. 4. Reflect in y-axis. 5. Rotate 908 clockwise. 6. Translate left 5 units. 7. Rotate 908 counterclockwise. 8. Translate right 2 units and down 9 units. Transform n PST. Graph the result. For rotations, rotate about the origin. 9. Reflect in x-axis. y T 10. Rotate 908 counterclockwise. 11. Rotate 908 clockwise. 12. Translate down 7 units. 13. Reflect in y-axis. 14. Translate left 4 units. 15. Rotate 1808. 16. Translate right 2 units. x 1 22 P S 17. Translate right 1 unit and up 4 units. 18. Translate left 6 units and up 2 units. The coordinates of the vertices of a polygon are given. Draw the polygon. Then find the coordinates of the vertices of the image after the specified dilation, and draw the image. 19. (1, 3), (3, 2), (2, 5); dilate using a scale factor of 3 3 20. (2, 8), (2, 4), (6, 8), (6, 4); dilate using a scale factor of } 2 1 21. (3, 3), (6, 3), (3, 23), (6, 23); dilate using a scale factor of } 3 22. (2, 2), (2, 7), (5, 7); dilate using a scale factor of 2 1 23. (2, 22), (6, 22), (4, 26), (0, 26); dilate using a scale factor of } 2 Skills Review Handbook n2pe-9020.indd 989 989 11/21/05 10:27:02 AM SKILLS REVIEW HANDBOOK Line Symmetry A figure has line symmetry if a line, called a line of symmetry, divides the figure into two parts that are mirror images of each other. Below are four figures with their lines of symmetry shown in red. Trapezoid No lines of symmetry EXAMPLE Isosceles Triangle 1 line of symmetry Rectangle 2 lines of symmetry Regular Hexagon 6 lines of symmetry A line of symmetry for the figure is shown in red. Find the coordinates of point A. Point A is the mirror image of the point (3, 26) with respect to the line of symmetry y 5 22. The x-coordinate of A is 3, the same as the x-coordinate of (3, 26). Because 26 is the y-coordinate of (3, 26), and 22 2 (26) 5 4, the point (3, 26) is down 4 units from the line of symmetry. Therefore, point A must be up 4 units from the line of symmetry. So, the y-coordinate of A is 22 1 4 5 2. The coordinates of point A are (3, 2). y A 1 x 2 y 5 22 C B(3, 26) PRACTICE Tell how many lines of symmetry the figure has. 1. 2. 3. 4. 5. A parallelogram 6. A square 7. A rhombus 8. An equilateral triangle A line of symmetry for the figure is shown in red. Find the coordinates of point A. 9. 4 (24, 3) 10. y 11. y (0, 4) A 1x 990 n2pe-9020.indd 990 y5x 1 y51 A y A x52 1 1 1 x x (2, 22) Student Resources 11/21/05 10:27:03 AM Perimeter and Area SKILLS REVIEW HANDBOOK The perimeter P of a figure is the distance around it. To find the perimeter of a figure, add the side lengths. EXAMPLE Find the perimeter of the figure. a. b. 13 in. 5 in. 18 m 4m 4m 18 m 12 in. P 5 5 1 12 1 13 5 30 in. P 5 2(4) 1 2(18) 5 8 1 36 5 44 m The area A of a figure is the number of square units enclosed by the figure. Area of a Triangle Area of a Rectangle Area of a Parallelogram Area of a Trapezoid b1 h w h l b 1 2 b A 5 lw A 5 }bh EXAMPLE h b2 1 2 A 5 }(b1 1 b2)h A 5 bh Find the area of the figure. a. b. c. 7 in. 6m 5 ft 3m 15 in. A 5 (15)(7) 5 105 in.2 A 5 (5)(5) 5 25 ft 2 1 (6)(3) 5 9 m 2 A5} 2 PRACTICE Find the perimeter and area of the figure. 1. 2. 8 ft 3 cm 17 ft 3. 3 in. 15 ft 4. 4 in. 5 in. 5m 12 in. 6m 2 cm 5. 6. 10 yd 8 yd 7. 8. 12 mm 17 yd 8 in. 2.7 m 3m 9 mm 9 mm 21 yd 4m 12 mm Skills Review Handbook n2pe-9020.indd 991 991 11/21/05 10:27:04 AM SKILLS REVIEW HANDBOOK Circumference and Area of a Circle A circle consists of all points in a plane that are the same distance from a fixed point called the center. The distance between the center and any point on the circle is the radius. The distance across the circle through the center is the diameter. The diameter is twice the radius. circle radius diameter center The circumference of a circle is the distance around the circle. For any circle, the ratio of the circumference to the diameter is π (pi), an irrational number 22 . that is approximately 3.14 or }} 7 To find the circumference C of a circle with radius r, use the formula C 5 2πr. To find the area A of a circle with radius r, use the formula A 5 πr 2. EXAMPLE Find the circumference and area of a circle with radius 6 cm. Give an exact answer and an approximate answer for each. Circumference Area C 5 2πr A 5 πr 2 5 2π(6) 5 π(6)2 5 12π 5 36π < 12(3.14) < 36(3.14) < 37.7 < 113 c The circumference is 12π centimeters, or about 37.7 centimeters. 6 cm c The area is 36π square centimeters, or about 113 square centimeters. PRACTICE Find the circumference and area of the circle. Give an exact answer and an approximate answer for each. 1. 2. 3. 4. 5 in. 10 m 2 cm 5. 6. 4 in. 7. 8. 6 ft 12 ft 16 m 9 cm 9. 10. 2 cm 992 n2pe-9020.indd 992 11. 14 ft 12. 22 in. 36 cm Student Resources 11/21/05 10:27:05 AM Surface Area and Volume SKILLS REVIEW HANDBOOK A solid is a three-dimensional figure that encloses part of space. The surface area S of a solid is the area of the solid’s outer surface(s). The volume V of a solid is the amount of space that the solid occupies. Cylinder Rectangular Prism h S 5 2lw 1 2lh 1 2wh V 5 lwh w l EXAMPLE r 2 S 5 2πr 1 2πrh h V 5 πr 2h Find the surface area and volume of the rectangular prism. Surface area Volume S 5 2lw 1 2lh 1 2wh V 5 lwh 7 ft 5 2(5)(3) 1 2(5)(7) 1 2(3)(7) 5 (5)(3)(7) 5 30 1 70 1 42 5 105 ft 3 5 ft 3 ft 5 142 ft 2 EXAMPLE Find the surface area and volume of the cylinder. Surface area 3m Volume 2 12 m 2 V 5 πr h S 5 2πr 1 2πrh 2 5 2π(3) 1 2π(3)(12) 5 π(3)2 (12) 5 90π m 2 Exact answer 5 108π m3 Exact answer < 283 m 2 Approximate answer < 339 m3 Approximate answer PRACTICE Find the surface area and volume of the solid. 1. 2. 6.5 mm 3. 3 in. 3 cm 12 mm 5 in. 3 cm 3 cm 8 in. 4. 2m 4m 5. 6. 14 yd 10 ft 4 yd 10 m 15 ft Skills Review Handbook n2pe-9020.indd 993 993 11/21/05 10:27:07 AM SKILLS REVIEW HANDBOOK Angle Relationships An angle bisector is a ray that divides an angle into two congruent angles. Two angles are complementary angles if the sum of their measures is 908. Two angles are supplementary angles if the sum of their measures is 1808. EXAMPLE Find the value of x. ]› a. BD bisects ∠ ABC and m ∠ ABC 5 648. C b. ∠ GFJ and ∠ HFJ are J D x8 648 ]› Because BD bisects ∠ ABC, the value of x is half m ∠ ABC. 64 5 32 x 5 }} 2 D 4x 8 (3x 2 1)8 F G A supplementary. H (2x 2 6)8 B c. ∠ CBD and ∠ ABD are complementary. E C Because ∠ GFJ and ∠ HFJ are complementary angles, their sum is 908. (x 2 3)8 B A Because ∠ CBD and ∠ ABD are supplementary angles, their sum is 1808. (2x 2 6) 1 4x 5 90 (3x 2 1) 1 (x 2 3) 5 180 6x 2 6 5 90 4x 2 4 5 180 x 5 16 x 5 46 PRACTICE ]› BD is the angle bisector of ∠ ABC. Find the value of x. 1. 2. A D 3. A D 248 788 x8 C B A (11x 2 19)8 (8x 1 5)8 B (2x 2 4)8 B D C C ∠ ABD and ∠ DBC are complementary. Find the value of x. 4. 5. A 6. B D A A (3x 2 18)8 (3x 2 4)8 (7x 1 5)8 D (4x 1 10)8 B D (5x 2 20)8 C (5x 1 1)8 C C B ∠ ABD and ∠ DBC are supplementary. Find the value of x. 7. 8. D (x 2 28)8 (4x 1 17)8 (3x 1 2)8 A 994 n2pe-9020.indd 994 B A C 9. D D 3x 8 B (4x 1 2)8 (2x 1 4)8 C A B C Student Resources 11/21/05 10:27:08 AM Triangle Relationships SKILLS REVIEW HANDBOOK The sum of the angle measures of any triangle is 1808. EXAMPLE Find the value of x. 60 1 35 1 x 5 180 x8 95 1 x 5 180 608 358 x 5 85 The sum of the angle measures is 1808. Simplify. Solve for x. In a right triangle, the hypotenuse is the side opposite the right angle. The legs are the sides that form the right angle. The Pythagorean theorem states that the sum of the squares of the lengths of the legs equals the square of the length of the hypotenuse. Pythagorean Theorem a2 1 b2 5 c 2 c a b EXAMPLE Find the value of x. a. b. 12 cm x 6 ft x 13 cm 8 ft 6 2 1 82 5 x 2 2 Simplify. 100 5 x2 Simplify. 36 1 64 5 x x 5 10 ft x2 1 122 5 132 Pythagorean theorem Pythagorean theorem 2 x 1 144 5 169 Simplify. x2 5 25 Solve for x2 . x 5 5 cm Solve for x. Solve for x. PRACTICE Find the value of x. 1. 2. 688 378 3. x8 4. x8 348 728 x8 x8 5. 6. 40 cm x 568 x8 7. 8 in. 8 in. x x8 37 ft 35 ft 30 cm 8. 5m 6m x x 9. A triangle with angles that measure x8, x8, and 708 Skills Review Handbook n2pe-9020.indd 995 995 11/21/05 10:27:09 AM SKILLS REVIEW HANDBOOK Congruent and Similar Figures Two figures are congruent if they have the same shape and the same size. If two figures are congruent, then corresponding angles are congruent and corresponding sides are congruent. The triangles at the right are congruent. Matching arcs show congruent angles, and matching tick marks show congruent sides. Two figures are similar if they have the same shape but not necessarily the same size. If two figures are similar, then corresponding angles are congruent and the ratios of the lengths of corresponding sides are equal. EXAMPLE Tell whether the figures are congruent, similar, or neither. a. 7 3 3 3 3 7 7 b. 10 11 As shown, corresponding angles are congruent, but corresponding sides have different lengths. So, the figures are not congruent, but they may be similar. F 3.75 E A 3 B D As shown, corresponding angles are congruent and corresponding sides are congruent. So, the figures are congruent. 7 6 7.5 C G 12.5 13.75 H The figures are similar if the ratios of the lengths of corresponding sides are equal. BC FG 3 3.75 AB EF }} 5 }} 5 0.8 6 7.5 }} 5 }} 5 0.8 CD GH 11 13.75 }} 5 }}} 5 0.8 AD EH 10 12.5 }} 5 }} 5 0.8 c Because corresponding angles are congruent and the ratios of the lengths of corresponding sides are equal, ABCD is similar to EFGH. EXAMPLE The two polygons are similar. Find the value of x. a. 608 x8 The angle with measure x° corresponds to the angle with measure 60°, so x 5 60. 308 b. 8 12 x 9 The side with length 12 corresponds to the side with length 8, and the side with length 9 corresponds to the side with length x. 12 8 9 x }} 5 } 12x 5 72 x56 996 n2pe-9020.indd 996 Write a proportion. Cross multiply. Solve for x. Student Resources 11/21/05 10:27:10 AM PRACTICE SKILLS REVIEW HANDBOOK Tell whether the figures are congruent, similar, or neither. Explain. 1. 2. 4 2 6 14 11 3.5 2 3. 1 10 7 14 3 4. 5. 7 6. 8 12 9 9 7 7 12 8 8. 6 4.5 9 1.5 12 1.6 3.2 5 1.5 3 9. 2.4 4.8 4 3 3 8 8 5 7. 12 6 4.8 7 3 3.2 7 1.6 3 3 2.4 The two polygons are similar. Find the value of x. 10. 11. 438 7 x21 12. 12 14 20 18 8 4x 1 3 x8 13. 14. 1138 34.5 27 15. 568 568 678 (5x 2 3)8 16. 18 17. 538 568 568 1248 5x 2 7 538 18. 1198 618 1198 36 15 30 x15 (3x 1 4)8 (11x 2 5)8 1198 618 (7x 1 4)8 538 Skills Review Handbook n2pe-9020.indd 997 997 11/21/05 10:27:11 AM SKILLS REVIEW HANDBOOK More Problem Solving Strategies Problem solving strategies can help you solve mathematical and real-life problems. Lesson 1.5 shows how to apply the strategies use a formula, look for a pattern, draw a diagram, and use a verbal model. Below are four more strategies. Strategy When to Use How to Use Make a list or table Make a list or table when a problem requires you to record, generate, or organize information. Make a table with columns, rows, and any given information. Generate a systematic list that can help you solve the problem. Work backward Work backward when a problem gives you an end result and you need to find beginning conditions. Work backward from the given information until you solve the problem. Work forward through the problem to check your answer. Guess, check, and revise Guess, check, and revise when you need a place to start or you want to see how the problem works. Make a reasonable guess. Check to see if your guess solves the problem. If it does not, revise your guess and check again. Solve a simpler problem Solve a simpler problem when a problem can be made easier by using simpler numbers. Think of a way to make the problem simpler. Solve the simpler problem, then use what you learned to solve the original problem. EXAMPLE Lee works as a cashier. In how many different ways can Lee make $.50 in change using quarters, dimes, and nickels? Use the strategy make a list or table. Then count the number of different ways. Quarters Dimes Nickels 2 0 0 1 2 1 1 1 3 1 0 5 0 5 0 0 4 2 0 3 4 0 2 6 0 1 8 0 0 10 Start with the greatest number of quarters. Then list all the possibilities with 1 quarter, starting with the greatest number of dimes. Then list all the possibilities with 0 quarters, starting with the greatest number of dimes. c Lee can make $.50 in quarters, dimes, and nickels in 10 different ways. EXAMPLE In a cafeteria, 3 cookies cost $.50 less than a sandwich. If a sandwich costs $4.25, how much does one cookie cost? Use the strategy work backward. 4.25 2 0.50 5 3.75 Cost of 3 cookies 3.75 4 3 5 1.25 Cost of 1 cookie CHECK 1.25 3 3 5 3.75 Cost of 3 cookies 3.75 1 0.50 5 4.25 Cost of sandwich c One cookie costs $1.25. 998 n2pe-9020.indd 998 Student Resources 11/21/05 10:27:12 AM Nolan’s class has 6 more boys than girls. There are 28 students altogether. How many girls are in Nolan’s class? Use the strategy guess, check, and revise. Guess a number of girls that is less than half of 28. First guess: 12 girls, 12 1 6 5 18 boys, 12 1 18 5 30 students Too high ✗ Second guess: 10 girls, 10 1 6 5 16 boys, 10 1 16 5 26 students Too low ✗ Third guess: Correct ✓ 11 girls, 11 1 6 5 17 boys, 11 1 17 5 28 students c There are 11 girls in Nolan’s class. EXAMPLE SKILLS REVIEW HANDBOOK EXAMPLE How many diagonals does a regular decagon have? Use the strategy solve a simpler problem. A decagon has 10 sides, so find the number of diagonals of polygons with fewer sides and look for a pattern. 3 sides 0 diagonals 4 sides 2 diagonals 5 sides 5 diagonals 6 sides 9 diagonals 7 sides 14 diagonals Notice that the difference of the numbers of diagonals for consecutive figures keeps increasing by 1: 22052 52253 92554 14 2 9 5 5 So, an 8-sided polygon has 14 1 6 5 20 diagonals, a 9-sided polygon has 20 1 7 5 27 diagonals, and a 10-sided polygon has 27 1 8 5 35 diagonals. c A regular decagon (a 10-sided polygon) has 35 diagonals. PRACTICE 1. Ben has a concert at 7:30 P.M. First he must do 2 hours of homework. Then, dinner and a shower will take about 45 minutes. Ben wants to allow a half hour to get to the concert. What time should Ben start his homework? 2. Quinn and Kyle collected 87 aluminum cans to recycle. Quinn collected twice as many cans as Kyle. How many cans did each person collect? 3. In how many different ways can three sisters form a line at a ticket booth? 4. The 8 3 8 grid at the right has some 1 3 1 squares, some 2 3 2 squares, some 3 3 3 squares, and so on. How many total squares does the grid have? 5. If Kaleigh draws 20 different diameters in a circle, into how many parts will the circle be divided? 6. Six friends form a tennis league. Each friend will play a match with every other friend. How many matches will be played? 7. Susan has 13 coins in her pocket with a total value of $1.05. She has only dimes and nickels. How many of each type of coin does Susan have? Skills Review Handbook n2pe-9020.indd 999 999 11/21/05 10:27:13 AM SKILLS REVIEW HANDBOOK Logical Argument A logical argument has two given statements, called premises, and a statement, called a conclusion, that follows from the premises. Below is an example. Premise 1 Premise 2 Conclusion If a triangle has a right angle, then it is a right triangle. In nABC, ∠B is a right angle. nABC is a right triangle. Letters are often used to represent the statements of a logical argument and to write a pattern for the argument. The table below gives five types of logical arguments. In the examples, p, q, and r represent the following statements. p: a figure is a square Type of Argument q: a figure is a rectangle Pattern r: a figure is a parallelogram Example Direct Argument If p is true, then q is true. p is true. Therefore, q is true. If ABCD is a square, then it is a rectangle. ABCD is a square. Therefore, ABCD is a rectangle. Indirect Argument If p is true, then q is true. q is not true. Therefore, p is not true. If ABCD is a square, then it is a rectangle. ABCD is not a rectangle. Therefore, ABCD is not a square. Chain Rule If p is true, then q is true. If q is true, then r is true. Therefore, if p, then r. If ABCD is a square, then it is a rectangle. If ABCD is a rectangle, then it is a parallelogram. Therefore, if ABCD is a square, then it is a parallelogram. Or Rule p is true or q is true. p is not true. Therefore, q is true. ABCD is a square or a rectangle. ABCD is not a square. Therefore, ABCD is a rectangle. And Rule p and q are not both true. q is true. Therefore, p is not true. ABCD is not both a square and a rectangle. ABCD is a rectangle. Therefore, ABCD is not a square. An argument that follows one of these patterns correctly has a valid conclusion. EXAMPLE State whether the conclusion is valid or invalid. If the conclusion is valid, name the type of logical argument used. a. If it is raining at noon, Peter’s family will not have a picnic lunch. Peter’s family had a picnic lunch. Therefore, it was not raining at noon. c The conclusion is valid. This is an example of indirect argument. b. If a triangle is equilateral, then it is an acute triangle. Triangle XYZ is an acute triangle. Therefore, triangle XYZ is equilateral. c The conclusion is invalid. c. If x 5 4, then 2x 2 7 5 1. If 2x 2 7 5 1, then 2x 5 8. x 5 4. Therefore, if x 5 4, then 2x 5 8. c The conclusion is valid. This is an example of the chain rule. d. If it is at least 808F outside today, you will go swimming. It is 858F outside today. Therefore, you will go swimming. c The conclusion is valid. This is an example of direct argument. 1000 Student Resources n2pe-9020.indd 1000 11/21/05 10:27:14 AM A compound statement has two or more parts joined by or or and. • For an or compound statement to be true, at least one part must be true. EXAMPLE State whether the compound statement is true or false. a. 12 < 20 and 212 > 220 True b. 2 < 4 and 4 < 3 True True c True, because each part is true. c. 10 > 0 or 210 > 0 True False c False, because one part is false. d. 28 > 27 or 27 > 26 or 26 > 25 False False c True, because at least one part is true. False SKILLS REVIEW HANDBOOK • For an and compound statement to be true, each part must be true. False c False, because every part is false. PRACTICE State whether the conclusion is valid or invalid. If the conclusion is valid, name the type of logical argument used. 1. If Scott goes to the store, then he will buy sugar. If he buys sugar, then he will bake cookies. Scott goes to the store. Therefore, he will bake cookies. 2. If a triangle has at least two congruent sides, then it is isosceles. Triangle MNP has sides 5 in., 6 in., and 5 in. long. Therefore, triangle MNP is isosceles. 3. If a horse is an Arabian, then it is less than 16 hands tall. Andrea’s horse is 13 hands tall. Therefore, Andrea’s horse is an Arabian. 4. If a figure is a rhombus, then it has four sides. Figure WXYZ has four sides. Therefore, WXYZ is a rhombus. 5. Jeff cannot buy both a new coat and new boots. Jeff decides to buy new boots. Therefore, Jeff cannot buy a new coat. 6. If x 5 0, then y 5 4. If y 5 4, then z 5 7. Therefore, if z 5 7, then x 5 0. 7. Kate will order either tacos or burritos for lunch. Kate does not order tacos for lunch. Therefore, Kate orders burritos for lunch. 8. If a triangle is equilateral, then it is equiangular. Triangle ABC is not equiangular. Therefore, triangle ABC is not equilateral. 9. An animal cannot be both a fish and a bird. Courtney’s pet is not a fish. Therefore, Courtney’s pet must be a bird. State whether the compound statement is true or false. 10. 27 < 25 and 25 < 26 11. 6 > 2 or 8 < 4 12. 0 ≤ 21 or 5 ≥ 5 13. 4 ≤ 3 or 12 ≥ 13 14. 3 < 5 and 23 < 25 15. 1 5 21 or 1 5 1 or 1 5 0 16. 7 < 8 and 8 < 12 17. 22 < 2 and 3 ≥ 2 18. 3(24) 5 12 or 23(4) 5 12 19. 28 > 8 or 28 5 8 or 28 ≥ 0 20. 140 Þ 145 or 140 > 2145 or 2140 < 2145 21. 28(9) 5 272 and 8(29) 5 272 22. 22 ≤ 23 and 222 < 223 and 23 > 22 Skills Review Handbook n2pe-9020.indd 1001 1001 11/21/05 10:27:15 AM SKILLS REVIEW HANDBOOK Conditional Statements and Counterexamples A conditional statement has two parts, a hypothesis and a conclusion. When a conditional statement is written in if-then form, the “if” part contains the hypothesis and the “then” part contains the conclusion. An example of a conditional statement is shown below. If a triangle is equiangular, then each angle of the triangle measures 608. Hypothesis Conclusion The converse of a conditional statement is formed by switching the hypothesis and the conclusion. The converse of the statement above is as follows: If each angle of a triangle measures 608, then the triangle is equiangular. EXAMPLE Rewrite the conditional statement in if-then form. Then write its converse and tell whether the converse is true or false. a. Bob will earn $20 by mowing the lawn. If-then form: If Bob mows the lawn, then he will earn $20. Converse: If Bob earns $20, then he mowed the lawn. False b. x 5 8 when 5x 1 1 5 41. If-then form: If 5x 1 1 5 41, then x 5 8. Converse: If x 5 8, then 5x 1 1 5 41. True A biconditional statement is a statement that has the words “if and only if.” You can write a conditional statement and its converse together as a biconditional statement. A triangle is equiangular if and only if each angle of the triangle measures 608. A biconditional statement is true only when the conditional statement and its converse are both true. EXAMPLE Tell whether the biconditional statement is true or false. Explain. a. An angle measures 90° if and only if it is a right angle. Conditional: If an angle is a right angle, then it measures 908. True Converse: If an angle measures 908, then it is a right angle. True c The biconditional statement is true because the conditional and its converse are both true. b. Bonnie has $.50 if and only if she has two quarters. Conditional: If Bonnie has two quarters, then she has $.50. True Converse: If Bonnie has $.50, then she has two quarters. False c The biconditional statement is false because the converse is not true. 1002 Student Resources n2pe-9020.indd 1002 11/21/05 10:27:17 AM A counterexample is an example that shows that a statement is false. SKILLS REVIEW HANDBOOK EXAMPLE Tell whether the statement is true or false. If false, give a counterexample. a. If a polygon has four sides and opposite sides are parallel, then it is a rectangle. c False. A counterexample is the parallelogram shown. b. If x2 5 49, then x 5 7. c False. A counterexample is x 5 27, because (27)2 5 49. PRACTICE Rewrite the conditional statement in if-then form. Then write its converse and tell whether the converse is true or false. 1. The graph of the equation y 5 mx 1 b is a line. 2. You will earn $35 for working 5 hours. 3. Abby can go swimming if she finishes her homework. 4. In a right triangle, the sum of the squares of the lengths of the legs equals the square of the length of the hypotenuse. 5. x 5 5 when 4x 1 8 5 28. 6. The sum of two even numbers is an even number. Tell whether the biconditional statement is true or false. Explain. 7. Two lines are perpendicular if and only if they intersect to form a right angle. 8. x 3 5 27 if and only if x 5 3. 9. A vegetable is a carrot if and only if it is orange. 10. A rhombus is a square if and only if it has four right angles. 11. The graph of a function is a parabola if and only if the function is y 5 x2. 12. An integer is odd if and only if it is not even. Tell whether the statement is true or false. If false, give a counterexample. 13. If an integer is not negative, then it is positive. 14. If you were born in the summer, then you were born in July. 15. If a polygon has exactly 5 congruent sides, then the polygon is a pentagon. 16. If x 5 26, then x2 5 36. 17. If B is 6 inches from A and 8 inches from C, then A is 14 inches from C. 18. If a triangle is isosceles, then it is obtuse. 19. If Charlie has $1.00 in coins, then he has four quarters. 20. If you are in Montana, then you are in the United States. Skills Review Handbook n2pe-9020.indd 1003 1003 11/21/05 10:27:18 AM SKILLS REVIEW HANDBOOK Venn Diagrams A Venn diagram uses shapes to show how sets are related. EXAMPLE Draw a Venn diagram of the positive integers less than 13 where set A consists of factors of 12 and set B consists of even numbers. Positive integers less than 13: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 Positive integers less than 13 A Set A (factors of 12): 1, 2, 3, 4, 6, 12 1 Set B (even numbers): 2, 4, 6, 8, 10, 12 Both set A and set B: 2, 4, 6, 12 B 2 4 3 6 8 12 10 5 11 7 9 Neither set A nor set B: 5, 7, 9, 11 EXAMPLE Use the Venn diagram above to decide if the statement is true or false. Explain your reasoning. a. If a positive integer less than 13 is not even, then it is not a factor of 12. c False. 1 and 3 are not even, but they are factors of 12. b. All positive integers less than 13 that are even are factors of 12. c False. 8 and 10 are even, but they are not factors of 12. PRACTICE Draw a Venn diagram of the sets described. 1. Of the positive integers less than 11, set A consists of factors of 10 and set B consists of odd numbers. 2. Of the positive integers less than 10, set A consists of prime numbers and set B consists of even numbers. 3. Of the positive integers less than 25, set A consists of multiples of 3 and set B consists of multiples of 4. Use the Venn diagrams you drew in Exercises 1–3 to decide if the statement is true or false. Explain your reasoning. 4. The only factors of 10 less than 11 that are not odd are 2 and 10. 5. If a number is neither a multiple of 3 nor a multiple of 4, then it is odd. 6. All prime numbers less than 10 are not even. 7. If a positive odd integer less than 11 is a factor of 10, then it is 5. 8. There are 2 positive integers less than 25 that are both a multiple of 3 and a multiple of 4. 9. If a positive even integer less than 10 is prime, then it is 2. 1004 Student Resources n2pe-9020.indd 1004 11/21/05 10:27:19 AM Mean, Median, Mode, and Range The mean of a data set is the sum of the values divided by the number of values. The mean is also called the average. EXAMPLE The median of a data set is the middle value when the values are written in numerical order. If a data set has an even number of values, the median is the mean of the two middle values. The mode of a data set is the value that occurs most often. A data set can have no mode, one mode, or more than one mode. The range of a data set is the difference between the greatest value and the least value. SKILLS REVIEW HANDBOOK Mean, median, and mode are measures of central tendency; they measure the center of data. Range is a measure of dispersion; it measures the spread of data. Find the mean, median, mode(s), and range of the data. Daily High Temperatures, Week of June 21–27 Day Sunday Monday Tuesday Wednesday Thursday Friday Saturday 76 74 70 69 70 75 78 Temperature (8F) Mean Add the values. Then divide by the number of values. 76 1 74 1 70 1 69 1 70 1 75 1 78 5 512 mean 5 512 4 7 ø 73 The mean of the data is about 738F. Median Write the values in order from least to greatest. Find the middle value(s). 69, 70, 70, 74, 75, 76, 78 median 5 74 Mode Find the value that occurs most often. mode 5 70 Range The median of the data is 748F. The mode of the data is 708F. Subtract the least value from the greatest value. range 5 78 2 69 5 9 The range of the data is 98F. PRACTICE Find the mean, median, mode(s), and range of the data. 1. Apartment rents: $650, $800, $700, $525, $675, $750, $500, $650, $725 2. Ages of new drivers: 15, 15, 15, 15, 16, 16, 16, 16, 16, 17, 17, 17, 18, 18 3. Monthly cell-phone minutes: 581, 713, 423, 852, 948, 337, 810, 604, 897 4. Prices of a CD: $12.98, $14.99, $13.49, $12.98, $13.89, $16.98, $11.98 5. Cookies in a batch: 36, 60, 52, 44, 48, 45, 48, 41, 60, 45, 38, 55, 60, 48, 40 6. Ages of family members: 41, 45, 8, 10, 40, 44, 3, 5, 42, 42, 13, 14, 67, 70 7. Hourly rates of pay: $8.80, $6.50, $10.85, $7.90, $9.50, $9, $8.70, $12.35 8. Weekly quiz scores: 8, 9, 8, 10, 10, 7, 9, 8, 9, 9, 10, 7, 8, 6, 10, 9, 9, 8, 8, 10 9. People on a bus: 9, 14, 5, 22, 18, 30, 6, 25, 18, 12, 15, 10, 8, 22, 10, 11, 20 Skills Review Handbook n2pe-9020.indd 1005 1005 11/21/05 10:27:20 AM SKILLS REVIEW HANDBOOK Graphing Statistical Data There are many ways to display data. An appropriate graph can help you analyze data. The table at the right summarizes how data are shown in some statistical graphs. EXAMPLE Bar Graph Compares data in categories. Circle Graph Compares data as parts of a whole. Line Graph Shows data change over time. Use the bar graph to answer the questions. a. On which day of the week were the greatest Cars Parked in Student Lot number of cars parked in the student lot? 120 b. How many cars were parked in the student lot on Monday? 80 Cars c The tallest bar on the graph is for Friday. So, the answer is Friday. 40 c The bar for Monday shows that about 70 cars were parked in the student lot. EXAMPLE 0 Tu W Th F Use the circle graph to answer the questions. a. Which type of transportation is used almost half the Transportation to School time? Car 45% Bus 20% c Almost half of the total area of the circle is labeled “Car 45%.” So, a car is used almost half the time. Walk or bike 35% b. Which type of transportation is used the least often? c The smallest part of the circle is labeled “Bus 20%.” So, a bus is used the least often. EXAMPLE M Use the line graph to answer the questions. a. In which month(s) was Jamie’s balance Jamie’s Savings Account Balance $250? b. Between which two consecutive months did Jamie’s balance increase the most? c Of the graph’s line segments that have positive slope, the graph is steepest from June to July. So, Jamie’s balance increased the most between June and July. 400 300 Dollars c The points on the graph to the right of $250 show that Jamie’s balance was $250 in May and December. 200 100 0 J F M A M J J A S O N D Month 1006 Student Resources n2pe-9020.indd 1006 11/21/05 10:27:21 AM PRACTICE Friday at Ferraro’s Restaurant 1. At which hour did Ferraro’s have 22 diners? 3. How many diners were at Ferraro’s at 11 P.M.? Were they gone by midnight? Diners 30 2. At which hour did Ferraro’s have the most diners? 20 10 0 4. Between which two consecutive hours did the 5 number of diners at Ferraro’s change the most? 6 7 8 9 10 11 Time (hours since noon) 12 5. How many fewer diners were at Ferraro’s at 10 P.M. than at 6 P.M.? Use the bar graph to answer Exercises 6–8. SKILLS REVIEW HANDBOOK Use the line graph to answer Exercises 1–5. Seasons of Students’ Birthdays 6. In which season were the fewest students born? 12 Students 7. In which season(s) were 7 students born? 8. How many more students were born in spring than in summer? 8 4 0 Use the circle graph to answer Exercises 9–11. Fall Winter Spring Summer Heat Sources for U.S. Homes 9. What is the heat source of more than half the Natural gas 52% Electricity 22% homes in the United States? 10. What percent of homes in the United States are Fuel oil 10% heated with electricity? Other 16% 11. If you randomly selected 500 U.S. homes, about how many would be heated with fuel oil? 12. The table below shows the high temperatures in degrees Fahrenheit for one week. Display the data in a line graph. Mon. Tues. Wed. Thurs. Fri. Sat. Sun. 83 89 79 73 69 67 71 13. A high school conducted a survey to determine the numbers of students involved in various school activities. Display the survey results in a bar graph. Computer club Music club Yearbook club Drama club Student council Chess club 34 75 16 57 28 12 14. The table below shows the items sold at a café in one day. Display the data in a circle graph. Juice Soda Water Muffin Cookie 95 180 100 55 40 Skills Review Handbook n2pe-9020.indd 1007 1007 11/21/05 10:27:22 AM SKILLS REVIEW HANDBOOK Organizing Statistical Data Because it is difficult to analyze unorganized data, it is helpful to organize data using a line plot, stem-and-leaf plot, histogram, or box-and-whisker plot. EXAMPLE Sydney’s math test scores are 90, 85, 88, 95, 100, 77, 85, 100, 80, 77, and 90. a. Draw a line plot to display the data. Make a number line from 75 to 100. Each time a value is listed in the data set, draw an X above the value on the number line. 75 3 3 3 3 3 3 3 3 3 3 3 77 80 85 88 90 95 100 b. Draw a stem-and-leaf plot to display the data. First write the leaves next to their stems. 7 7 7 8 5 8 5 9 0 5 0 10 0 Then order the leaves from least to greatest. 7 7 8 0 5 5 9 0 0 5 10 0 0 0 Key: 7 | 7 5 77 0 7 8 Key: 7 | 7 5 77 c. Draw a histogram to display the data. First make a frequency table. Use equal intervals. Then make a histogram. Sydney’s Math Test Scores Tally Frequency 71–80 3 3 81–90 5 5 91–100 3 3 6 Frequency Score 4 2 0 71–80 81– 90 Score 91–100 d. Draw a box-and-whisker plot to display the data. Write the data in order from least to greatest. Ordered data are divided into a lower half and an upper half by the median. The median of the lower half is the lower quartile, and the median of the upper half is the upper quartile. 77 77 Low value 80 Lower quartile 85 85 88 90 90 Median Plot the median, quartiles, and low and high values below a number line. Draw a box between quartiles with a vertical line through the median as shown. Draw whiskers to the low and high values. 95 100 100 Upper quartile High value Sydney’s Math Test Scores 75 80 77 80 85 90 88 95 100 95 100 1008 Student Resources n2pe-9020.indd 1008 11/21/05 10:27:23 AM PRACTICE SKILLS REVIEW HANDBOOK Use the following list of ticket prices to answer Exercises 1–4: $50, $42, $65, $54, $70, $65, $59, $30, $67, $49, $54, $30, $73, $47, and $54. 1. Draw a line plot to display the data. 2. How many ticket prices are $50 or less? 3. Draw a stem-and-leaf plot to display the data. 4. What is the range of ticket prices costs? Use the following list of hourly wages of employees to answer Exercises 5–8: $8.50, $6, $10, $14.25, $5.75, $7, $6.50, $14, $10, $9, $6.50, $8.25, $8.50, $11.25, $7, $16, $12, $6, $6.75. 5. Draw a histogram to display the data. Begin with the interval $5.00 to $6.99. 6. Copy and complete: The greatest number of employees earn from ? to ? per hour. 7. Draw a box-and-whisker plot to display the data. 8. Copy and complete: About half of the employees have an hourly wage of ? or less. Use the line plot, which shows the results of a survey asking people the average number of e-mails they receive daily, to answer Exercises 9 and 10. 9. Copy and complete: Most people surveyed receive an average of ? e-mails per day. 3 3 3 3 3 4 5 3 3 3 3 3 3 3 7 10 12 15 17 10. How many people receive an average of more than 10 e-mails per day? Use the stem-and-leaf plot, which shows the weights (in pounds) of dogs at an animal shelter, to answer Exercises 11–13. 11. How many dogs were at the shelter? 12. Find the median of the data. 2 2 5 5 9 3 1 3 5 8 4 0 0 1 2 2 5 6 7 5 0 3 5 8 9 6 4 5 Key: 2 | 2 5 22 13. Find the range of the data. Use the histogram to answer Exercises 14–16. Baseball Game Attendance 9 9 –6 60 –5 9 50 –4 40 –3 9 30 20 oldest group? –2 9 0 –1 9 16. Which age group had the same attendance as the 20 9 the baseball game? 40 10 15. How many children up to the age of 9 years attended 0– baseball game? Which had the least? People 14. Which age group had the greatest attendance at the Age (years) Use the box-and-whisker plot to answer Exercises 17–19. 17. What is the median number of songs on Sam’s CDs? Number of Songs on Sam’s CDs 10 12 14 10 11 12 14 16 18 18. What is the upper quartile of songs on Sam’s CDs? 19. What is the least number of songs on one of Sam’s CDs? What is the greatest number? 18 Skills Review Handbook n2pe-9020.indd 1009 1009 11/21/05 10:27:24 AM