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3-2 Study Guide and Intervention

Angles and Parallel Lines

Parallel Lines and Angle Pairs When two parallel lines are cut by a transversal, the following pairs of angles are congruent.

• corresponding angles

• alternate interior angles

• alternate exterior angles

Also, consecutive interior angles are supplementary.

Example: In the figure, m∠2 = 75. Find the measures of the remaining angles.

m∠1 = 105 ∠1 and ∠2 form a linear pair.

m∠3 = 105 ∠3 and ∠2 form a linear pair.

m∠4 = 75 ∠4 and ∠2 are vertical angles.

m∠5 = 105 ∠5 and ∠3 are alternate interior angles.

m∠6 = 75 ∠6 and ∠2 are corresponding angles.

m∠7 = 105 ∠7 and ∠3 are corresponding angles.

m∠8 = 75 ∠8 and ∠6 are vertical angles.

Exercises

In the figure, m∠3 = 102. Find the measure of each angle.

Tell which postulate(s) or theorem(s) you used.

1. ∠5 2. ∠6

3. ∠11 4. ∠7

5. ∠15 6. ∠14

In the figure, m∠9 = 80 and m∠5 = 68. Find the measure

of each angle. Tell which postulate(s) or theorem(s) you used.

7. ∠12 8. ∠1

9. ∠4 10. ∠3

11. ∠7 12. ∠16

3-2 Skills Practice

Angles and Parallel Lines

In the figure, m∠2 = 70. Find the measure of each angle.

1. ∠3 2. ∠5

3. ∠8 4. ∠1

5. ∠4 6. ∠6

In the figure, m∠7 = 100. Find the measure of each angle.

7. ∠9 8. ∠6

9. ∠8 10. ∠2

11. ∠5 12. ∠11

In the figure, m∠3 = 75 and m∠10 = 105. Find the measure of each angle.

13. ∠2 14. ∠5

15. ∠7 16. ∠15

17. ∠14 18. ∠9

Find the value of the variable(s) in each figure. Explain your reasoning.

19. 20.

21. 22.

Chapter 3 11 Glencoe Geometry