# 3 3 Parallel Lines and Transversals Section 3

• Slides: 14

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 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 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 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 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. 2 3 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. 1 3 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. 2 5 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. 1 + 4 = 180 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°. Copyright © by Holt, Rinehart and Winston. All Rights Reserved.