1. © Teacher Created Materials Determining Angle Measures when Parallel Lines Are Cut by a Transversal Today’s Lesson

2. © Teacher Created Materials Warm-Up Activity We will warm up today by finding angle measures.

3. © Teacher Created Materials These are supplementary angles. 150° x How can you find the missing angle without using a protractor? Supplementary angles add up to 180°.

4. © Teacher Created Materials x + 150 = 180 150° x The supplementary angles add up to 180 degrees. 30° x = 180 – 150 x = 30

5. © Teacher Created Materials 43° x How can you find the missing angle without using a protractor? These angles are vertical. Vertical angles have the same angle measure. x = 43°

6. © Teacher Created Materials 82° 32° x How can you find the missing angle of the triangle without using a protractor? What do you know about triangles that will help you find the missing angle? The sum of the triangle’s angles equals 180 degrees.

7. © Teacher Created Materials 82° 32° x The sum of the triangle’s angles equals 180 degrees. 82 + 32 + x = 180 114 + x = 180 x = 180 – 114 x = 66 66°

8. © Teacher Created Materials Today, you will focus on using patterns to find missing angles. Whole-Class Skills Lesson

9. © Teacher Created Materials Congruent Angles have the same measure in degrees 43°

10. © Teacher Created Materials Parallel Lines Are always the same distance apart. They will never intersect.

11. © Teacher Created Materials Transversal A line that crosses a pair of parallel lines.

12. © Teacher Created Materials Corresponding Angles Angles in the same position on parallel lines cut by a transversal are congruent. 1 2 3 4 A B C D

13. © Teacher Created Materials Corresponding Angles 1 2 3 4 A B C D

14. © Teacher Created Materials Supplementary angles add up to 180 degrees. Vertical angles have the same angle measure. The sum of the triangle’s angles equals 180 degrees.

15. © Teacher Created Materials Lines a and b are parallel. a b c 12 34 5 78 6 What types of angles do you see in this example? Supplementary, Vertical, and Corresponding Angles

16. © Teacher Created Materials Lines a and b are parallel. a b c 12 34 5 78 6 Can you name the corresponding angles? Angles 1 and 5 Angles 4 and 8 Angles 2 and 6 Angles 3 and 7

17. © Teacher Created Materials Lines a and b are parallel. a b c 12 34 5 78 6 Can you name the vertical angles? Angles 1 and 3 Angles 4 and 2 Angles 5 and 7 Angles 6 and 8

18. © Teacher Created Materials Lines a and b are parallel. a b c 12 34 5 78 6 Can you name some of the supplementary angles? Angles 1 and 2 Angles 2 and 3 Angles 3 and 4 Angles 4 and 1 Angles 5 and 6 Angles 6 and 7 Angles 7 and 8 Angles 5 and 8

19. © Teacher Created Materials Lines a and b are parallel. a b c 1102 34 5 78 6 If Angle 1 measures 110 degrees, what is the measure of Angle 3? 110°

20. © Teacher Created Materials Lines a and b are parallel. a b c 1102 34 5 78 6 If Angle 1 measures 110 degrees, what is the measure of Angle 4? 70°

21. © Teacher Created Materials Lines a and b are parallel. a b c 1102 34 5 78 6 If Angle 1 measures 110 degrees, what is the measure of Angle 8? 70°

22. © Teacher Created Materials Lines a and b are parallel. a b c 1102 34 5 78 6 If Angle 1 measures 110 degrees, what is the measure of Angle 7? 110°

23. © Teacher Created Materials Lines a and b are parallel. a b c 12 34 5 78 52° If Angle 6 measures 52 degrees, what is the measure of Angle 7? 128°

24. © Teacher Created Materials Lines a and b are parallel. a b c 12 34 5 78 52° If Angle 6 measures 52 degrees, what is the measure of all the angles on the diagram? 128° 52° 128° 52° 128°