1. Essential Question: How do you find angle measures?
Lesson 8.1 Angle Pairs
Essential Question: How do you find angle measures?

2. Before we start…
Find the measures of the numbered angles.

3. What is a straight angle?
An angle that measure 180°

4. What is a right angle?
An angle that measures 90°

5. How do you note the measure of an angle?
The measure of angle 1 is written as 𝑚∠1

6. What are supplementary angles?
Two angles whose measures add up to 180°
𝑚∠1+𝑚∠2=180°

7. What are complementary angles?
Two angles whose measures add up to 90°
𝑚∠3+𝑚∠4=90°

8. ∠1 and ∠2 are complementary, and 𝑚∠2=32°. Find 𝑚∠1.

9. Tell whether ∠1 and ∠2 are complementary, supplementary, or neither.
𝑚∠1=79° 𝑚∠2=101°
𝑚∠1=64° 𝑚∠2=36°

10. Tell whether ∠1 and ∠2 are complementary, supplementary, or neither.
𝑚∠1=52° 𝑚∠2=38°
𝑚∠1=44° 𝑚∠2=46°

11. Tell whether ∠1 and ∠2 are complementary, supplementary, or neither.
𝑚∠1=53° 𝑚∠2=47°
𝑚∠1=95° 𝑚∠2=85°

12. What are vertical angles?
A pair of angles that do not share a side that form when two lines intersect at a point. They ALWAYS have the same measure.
𝑚∠1=𝑚∠3
𝑚∠2=𝑚∠4

13. Find the angle measures indicated in the rug design if 𝑚∠1=122°.

14. Find the measures of the numbered angles.

15. Find the measures of the numbered angles.

16. Find the measures of the numbered angles. 𝑚∠1=133°.

17. What are perpendicular lines?
Two lines that intersect at a right angle.

18. What are parallel lines?
Two lines in the same plane that do not intersect

19. Angles and Parallel Lines

20. Use the diagram to find the angle measure.

21. Use the diagram to find the angle measure.

22. Use the diagram to find the angle measure.

23. How do you find angle measures. Use the information given
How do you find angle measures? Use the information given. - Supplementary angles add up to 180° - Complementary angles add up to 90° - Vertical angles are equal measures - Corresponding angles are equal measures - Alternate interior angles are equal - Alternate exterior angles are equal

24. Ticket Out the Door
Find 𝑚∠4