Download Review for Chapter 5 test

February 16, 2012
Activities
Review for
Chapter 5 test
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February 16, 2012
Ratios
Ratio: A comparison of two quantities by division.
Part to Part
Part to Whole
Whole to Part
Boys to Girls
Boys to Class
Class to Boys
3 ways to write a ratio:
5 to 12
5 : 12
5
12
How to Compare Ratios
5
12
45
108
1. Multiply the numbers diagonally
(From bottom to top).
2. Check the products (your answers)
to see if they are the same or not.
February 16, 2012
Boardwork
Are these Ra*o equivalent? Yes or No
1. 12:24 , 50:100
Yes or No
3. 2 to 3 ,
24 to 36
2. 22:1 , 1:22
Yes or No
4. 8 to 18 , 4 to 9
Yes or No
9. From 280 to 126
Yes or No
10.
From 59 to 127
February 16, 2012
Ratios
How to Make Equivalent Ratios
5
12
24
30
1. Multiply the top and bottom
numbers by any number.
2. Divide the top and bottom
numbers by any number.
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Boardwork
Find an Equivalent Ratio
1. 12:24
3. 2 to 3
2. 22:1
4. 8 to 18
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Unit Rate & Proportional Reasoning
Rate: A ratio that compares two quantities
Unit Rate:The rate for one unit of a given quantity.
Finding a Unit Rate.
EX: A package of cheddar cheese contains 15 servings
and has a total of 147 grams of fat. Find the unit rate of
grams of fat per serving.
1. Write the quantities as a ratio
according to what the problem asks.
grams
serving
Find the unit rate
of grams of fat per serving.
2. Set up your rate as a proportion.
(Make sure the 2nd rate has a
denominator of 1.)
3. Multiply diagonally and then
divide by the remaining number.
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1. Find the Unit rate for 210 heart beats in 3 minutes.
2. Find the unit rate for $33 for 4 hours of work.
February 16, 2012
Unit Rate & Proportional Reasoning
Rate: A ratio that compares two quantities
Unit Rate:The rate for one unit of a given quantity.
Finding Unit Cost by using Unit Rate.
EX: Dog food costs $.35/lb. How much does a 20 lb.
bag cost?
1. Write the Unit Rate as a ratio.
( BE SURE TO LABEL)
2. Set up your rate as a proportion.
(Extra information in problem
creates the 2nd ratio)
3. Multiply diagonally and then
divide by the remaining number.
Which bottle of Apple juice is the better buy: 48 fl oz for
$3.05 or 64 fl oz for $3.59?
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Proportions
* A Proportion is an equations stating that
two ratios are equal of two ratios. Ex
3
4
2
5
=
=
6
8
16
40
6 = 8
9
12
Check a proportion by multiplying cross
products.
3• 8 and 4 • 6
1. Multiply diagonally.
Start with the bottom number
and go to the top number.
2. Compare your answers to determine
if they are a proportion.
February 16, 2012
Determine whether the ratios form a proportion.
1.
3
6
=
16
8
2.
4
6
=
6
9
3.
5
4
= 9
8
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February 16, 2012
Solving Proportions
If postcards cost $2.45 for 5 cards. How much will 13 cards cost?
To find a missing number.
1. Make sure you line up labels
2. Circle diagonals and multiply the two
numbers.
3. Divide answer by the third remaining
number in the proportion.
3
4
=
20
x
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Solve each proportion.
1.
4.
12
x
=
21
15
2.
d
16
=
51
30
20
3. 110 =
35
m
Swimming goggles cost $84.36 for 12. How much will new
goggles for 17 members of a swimming team?
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Similar Figures
How to find a missing measure.
10
3
15
x
Small
left side
Small
long side
=
=
Big
right side
1. Make labels and match sides.
Big
long side
2. Fill in the measures.
EF
24
18
DC
=
16 • 18 ÷ 24 = x
x
3. Solve for missing measure.
Multiply diagonally then divide.
February 16, 2012
Similar Figures
How to find a missing measure.
Practice
32 cm
Y
X
40 cm
24 cm
30 cm
18 cm
X
Y
14 cm
6 cm
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Scale Drawings
The scale on a map is 1 in. = 40 miles. If it is 11 inches on a
map from Bemidji to Chicago, how many miles is it to Chicago?
=
1. Write your scale as a fraction with
the labels.
=
2. Add the measurement that you
are given from the problem.
=
3. Solve. Multiply diagonally then divide.
EF
24
Check
to see if they form a proportion.
18
DC
16 • 18 ÷ 24 = x
x
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February 16, 2012
The distance from Atlanta to Macon is about 75 mi. The scale on the map is 1
in. : 17 mi. What is the approximate map distance between these two cities?
February 16, 2012