Chapter 3.5, Problem 9PPS

To determine

To state the postulate or theorem justify the answer.

  $\angle 2\cong \angle 9$

Answer to Problem 9PPS

Theorem of alternate exterior angles

Explanation of Solution

Given information:

Figure

  $\angle 2\cong \angle 9$

Figure

Theorem of alternate exterior angles

When two lines are cut by a transversal and alternate exterior angles are congruent, then lines are parallel.

In figure $\angle 2$ is on the line u and transversal s and $\angle 9$ is on the line v and transversal s are congruent, means lines are parallel.

Then

In figure parallel lines are

  $u\left|\right|v$

Hence, $\angle 2\cong \angle 9$ are congruent.