Elementary Geometry for College Students (5th Edition)

1. Given 2. corresponding angles are congruence 3. vertical angles are congruence 4.m $\parallel$n 5. Corresponding angles are congruence 6.$\angle$1 $\cong$ $\angle$ 4, transitive properties proven
1. Given 2. As l and m are parallel then $\angle$1 and $\angle$2 that is corresponding angles are congruence 3. all vertical angles are congruence. Therefore $\angle$2 and $\angle$3 are congruent 4. the given statement is m $\parallel$ n 5. As m and n are parallel then $\angle$3 and $\angle$4 that is corresponding angles are congruence 6.by using transitive properties we can prove that $\angle$1 $\cong$ $\angle$ 4