Chapter 3 Lesson 1 Objective To indentify angles

Chapter 3 Lesson 1 Objective: To indentify angles formed by two lines and a transversal.

transversal: a line that intersects two coplanar lines at two distinct points. t l m transversal alternate interior angles: nonadjacent interior angles that lie on opposite sides of the transversal. t l 41 2 3 m

same-side interior angles: lie on the same side of the transversal and between l and m. t l 41 2 3 m corresponding angles: lie on the same side of the transversal and in corresponding positions relative to l and m. t l 56 41 m 2 3 7 8

Example 1: Identifying Angles Name a pair of alternate interior angles and a pair of -side interior angles. t 6 5 3 and 4 are alternate interior 4 1 angles 1 and angles. 3 are same-side interior 2 3 7 8 same l m

Example 2: Identifying Angles Name all pairs of corresponding angles. 5 and ; 6 and 2; 3; 4 and 1 and 7 8 t 56 4 1 2 3 7 8 l m

Example 3: Identifying Angles Identify which angle forms a pair of same-side interior angles with 1. Identify which angle forms a pair of corresponding angles with 1. Same-Side 8 41 3 2 8 5 7 6 Corresponding 5

Postulate 3 -1: Corresponding Angles Postulate If a transversal intersects two parallel lines, then corresponding angles are congruent. t 1 l 2 ► ► m Theorem 3 -1: Alternate Interior Angles Theorem If a transversal intersects two parallel lines, then alternate interior angles are congruent. t l ► 1 2 ► m

Theorem 3 -2: Same-Side Interior Angles Theorem If a transversal intersects two parallel lines, then same-side interior angles are supplementary. t 1 2 ► ► l m

Homework pg. 118 -120 #1 -8; 922; 26; 28