2. Main Idea and New Vocabulary Key Concept: Pairs of Angles
Example 1: Identify Angles
Example 2: Identify Angles
Example 3: Find a Missing Angle Measure
Lesson Menu

3. Identify complementary and supplementary angles and find missing angle measures.
complementary angles
supplementary angles
Main Idea/Vocabulary

4. Key Concept

5. Answer: Since 128° + 52° = 180°, the angles are supplementary.
Identify Angles
Identify the pair of angles as complementary, supplementary, or neither.
Answer: Since 128° + 52° = 180°, the angles are supplementary.
Example 1

6. Identify the pair of angles as complementary, supplementary, or neither.
A. complementary
B. supplementary
C. neither
Example 1 CYP

7. x and y form a right angle.
Identify Angles
Identify the pair of angles as complementary, supplementary, or neither.
x and y form a right angle.
Answer: So, the angles are complementary.
Example 2

8. Identify the pair of angles as complementary, supplementary, or neither.
A. complementary
B. supplementary
C. neither
Example 2 CYP

9. Find a Missing Angle Measure
ALGEBRA Find the value of x.
Since the two angles form a straight angle, they are supplementary.
Example 3

10. Find a Missing Angle Measure
56 + x = 180 Write the equation.
– – 56 Subtract 56 from each side.
x = 124
Answer: So, the value of x is 124.
Example 3

11. ALGEBRA Find the value of x.
C. 60
D. 80
Example 3 CYP