1-1a

1. (over Lesson 4-1) 1-1a Slide 1 of 2

2. (over Lesson 4-1) 1-1b Slide 1 of 2

3. Parallel Lines and Transversals What You'll Learn You will learn to identify the relationships among pairs of interior and exterior angles formed by two parallel linesand a transversal.

4. A l m B is an example of a transversal. It intercepts lines l and m. Parallel Lines and Transversals In geometry, a line, line segment, or ray that intersects two or more lines at different points is called a __________ transversal 2 1 4 3 5 6 8 7 Note all of the different angles formed at the points of intersection.

5. Parallel Lines Nonparallel Lines b l 2 1 2 1 3 4 4 3 m c 6 5 6 5 8 7 7 8 t r t is a transversal for l and m. r is a transversal for b and c. Parallel Lines and Transversals The lines cut by a transversal may or may not be parallel.

6. Exterior Interior Exterior Parallel Lines and Transversals Two lines divide the plane into three regions. The region between the lines is referred to as the interior. The two regions not between the lines is referred to as the exterior.

7. l 2 1 4 3 m 6 5 8 7 Parallel Lines and Transversals When a transversal intersects two lines, _____ angles are formed. eight These angles are given special names. t Exterior angles lie outside the two lines. Interior angles lie between the two lines. Alternate Interior angles are on the opposite sides of the transversal. Alternate Exterior angles are on the opposite sides of the transversal. Consectutive Interior angles are on the same side of the transversal. ?

8. Parallel Lines and Transversals congruent 2 1 4 3 6 5 7 8

9. 2 1 4 3 6 5 8 7 Parallel Lines and Transversals supplementary

10. 2 1 4 3 6 5 8 7 Parallel Lines and Transversals congruent ?

11. End of Lesson