1. PARALLEL LINES CUT BY A TRANSVERSAL

2. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals

3. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals If two parallel lines are cut by a transversal, then the pairs of corresponding angles are congruent

4. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals If two parallel lines are cut by a transversal, then the pairs of alternate interior angles are congruent

5. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals If two parallel lines are cut by a transversal, then the pairs of vertical angles are congruent

6. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals If two parallel lines are cut by a transversal, then the pairs of same-side interior angles are supplementary

7. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals If two parallel lines are cut by a transversal, then the pairs of alternate exterior angles are congruent

8. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals Find each angle measure. Example 1: Using the Corresponding Angles Postulate

9. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals Find mQRS.

10. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals Find each angle measure. Example 2: Finding Angle Measures A. mEDG B. mBDG

11. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals Example 3 Find mABD.

12. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals State the theorem or postulate that is related to the measures of the angles in each pair. Then find the unknown angle measures. 1. m1 = 120°, m2 = (60x)° 2. m2 = (75x – 30)°, m3 = (30x + 60)° 3. m3 = (50x + 20)°, m4= (100x – 80)° 4. m3 = (45x + 30)°, m5 = (25x + 10)°

13. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals Use the Converse of the Corresponding Angles Postulate and the given information to show that ℓ || m. Last 10! Using the Converse of the Corresponding Angles Postulate 4  8 4  8 4 and 8 are corresponding angles. ℓ || m Conv. of Corr. s Post.

14. Holt McDougal Geometry Angles Formed by Parallel Lines and Transversals LAST 10! Given: m3 = 2x, m7 = (x + 50), x = 50 Prove: r || s