Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
9.5 Angles and Triangles p.551 . D E .F Name the angle in five different ways. Angle DEF, angle FED, DEF, FED, or E . P Q .R Name the angle in five different ways. Angle PQR, angle RQP, PQR, RQP, or Q Classifying Angles p.553 o Right angle: An angle whose measure is 90 . o Straight angle: An angle whose measure is 180 . . . . C D E Acute angle: An angle whose measure is greater than 0o and less than 90o. Obtuse angle: An angle whose measure is greater than 90o and less than 180o. Classify the angles as right, straight, acute or obtuse. . . . Straight angle C D E Obtuse Angle Acute angle Right angle Complementary Angles p. 554 Two angles are complementary if the sum of their measures is 90o. Each angle is called a complement of the other. Find the measure of a complement of the angle. 1. 2. o 72 18o o 15 75o o 3. 45 45o Supplementary Angles p. 555 Two angles are supplementary if the sum of their measures is 180o. Each angle is called a supplement of the other. Find the supplement of the angle given. o 1. 38 o 142 o 2. 157 o 23 3. 90o o 90 Triangles p. 555 A triangle is a polygon made up of three segments, or sides. A triangle with vertices A, B, and C can be named ABC. I C F A B D E G H Types of Triangles p. 556 Equilateral triangle - All sides are the same length. Isosceles triangle – Two or more sides are the same length. Scalene triangle – All sides are of different lengths. Types of Triangles p. 556 Right triangle – One angle is a right angle. Obtuse triangle – One angle is an obtuse angle. Acute triangle – All three angles are acute. Sum of the Angle Measures of a Triangle In any triangle ABC, the sum of the measures of the angles is 180o. Find the measure of angle A. B x + 65o + 24o = 180o 65o A x o o x + 89 = 180 o 24 o o x = 180 – 89 C o x = 91