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

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

4. MA.8.G.2.2 Classify and determine the measure of angles, including angles created when parallel lines are cut by transversals.
NGSSS

5. Key Concept

6. 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

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

8. 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

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

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

11. 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

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

13. Identify the pair of angles as complementary, supplementary, or neither.
A. complementary
B. supplementary
C. neither
Five Minute Check 1

14. Identify the pair of angles as complementary, supplementary, or neither.
A. complementary
B. supplementary
C. neither
Five Minute Check 2

15. Identify the pair of angles as complementary, supplementary, or neither.
A. complementary
B. supplementary
C. neither
Five Minute Check 3

16. Find the value of x.
A. 55
B. 65
C. 145
D. 180
Five Minute Check 4

17. Tell whether the following statement is true or false
Tell whether the following statement is true or false. Angles are complementary if the sum of their measures is 180°.
A. true
B. false
Five Minute Check 5

18. 1 and 2 are complementary angles and m1 = 57°
1 and 2 are complementary angles and m1 = 57°. What is the measure of 2?
A. 33°
B. 43°
C. 57°
D. 123°
Five Minute Check 6