Chapter 12.1, Problem 21E

To determine

To Calculate: The other angle of a vertical angle pair when one angle is given.

Answer to Problem 21E

The measure of the angle that is vertical to an angle measuring ${140}^o$ is ${140}^o$ .

Explanation of Solution

Given Information: Two angles are a vertical angle pair and one of the angles is ${140}^o$ .

Concept Used: If two angles are vertical, then their measures are equal.

Calculation: Since $\angle 1$ and $\angle 2$ vertical angles,

  $m\angle 2=m\angle 1$

  $\Rightarrow m\angle 2={140}^o$$$

Therefore, the measure of the angle vertical to an angle measuring ${140}^o$ is $140^o$ .