Chapter 3.7, Problem 1PSA

To determine

To Prove: The congruency of the $\angle 1$ with respect to $\angle 2$

Explanation of Solution

Given information: $\overline{AB}\cong \overline{AC}$ provided in the question which will help to find the solution.

Proof: Here, $\overline{AB}\cong \overline{AC}$(as given in the question)

So, $\angle ABC=\angle ACB$ (Opposite sides of equal angles)

So that, $\angle 1+\angle ABC={180}^{\circ }$ (linear angle)

And, $\angle 2+\angle ACB={180}^{\circ }$ (Linear angle)

So that, $\angle 1+\angle ABC=\angle 2+\angle ACB$

Hence, $\angle 1\cong \angle 2$