Chapter 12.5, Problem 39E

To determine

To show: which angle in $△DEF$ is congruent to $\angle B.$

Answer to Problem 39E

  $\angle E$ is congruent to $\angle B.$

Explanation of Solution

Given information:

  

Formula used:

Two geometric figures are congruent if and only is a rigid motion or a composition of rigid motions maps one of the figures onto each other.

A rigid motion maps each part of a figure to a corresponding part of its image.

Calculation:

Consider the triangles given in the question,

  $△DEF$ is an mirror image of $△ABC.$

Therefore,

Corresponding angles are - $\angle C\cong \angle F,\angle A\cong \angle D,\angle B\cong \angle E.$

Hence, $\angle E$ is congruent to $\angle B.$