1. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. Section 3-3 Parallel lines and Transversals 3.3 Parallel Lines and Transversals

2. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Definitions Transversal: Is a line, ray or segment that intersects two or more coplanar lines, rays or segments each at a different point

3. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Definitions Alternate Interior Angles Are two nonadjacent interior angles that lie on opposite sides of a transversal

4. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Definitions Alternate Exterior Angles Are two nonadjacent exterior angles that lie on opposite sides of a transversal

5. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Definitions Same-Side Interior Angles Are interior angles that lie on the same side of a transversal

6. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Definitions Corresponding Angles Are two nonadjacent angles, one interior and one exterior, that lie on the same side of a transversal

7. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals 1) Identify pairs of angles. Corresponding angles Alternate interior angles Same-side interior angles Alternate exterior angles

8. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Theorems, Postulates, & Definitions Corresponding Angles Postulate 3.3.2: If two lines cut by a transversal are parallel, then corresponding angles are congruent. corresponding angles  2   3

9. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Theorems, Postulates, & Definitions Alternate Interior Angles Theorem 3.3.3: If two lines cut by a transversal are parallel, then alternate interior angles are congruent. alternate interior angles  1   3

10. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Theorems, Postulates, & Definitions Alternate Exterior Angles Theorem 3.3.4: If two lines cut by a transversal are parallel, then alternate exterior angles are congruent. alternate exterior angles  2   5

11. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals Theorems, Postulates, & Definitions Same-Side Interior Angles Theorem 3.3.5: If two lines cut by a transversal are parallel, then same-side interior angles are supplementary. same-side interior angles  1 +  4 = 180 

12. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals 2) Find angle measures formed by parallel lines and transversals. m || n and m  1 = 135°.

13. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. 3.3 Parallel Lines and Transversals 3)Given m || n and transversal t Prove:  1   3

14. Copyright © by Holt, Rinehart and Winston. All Rights Reserved. Assignment Page 159 # 5-10, 15, 22-33, 36 and 38