Question

question 10 of 10 what is the measure of $widehat{de}$?

Explanation:

Step1: Recall vertical - angle property

Vertical angles are equal. The angle at the center of the circle subtended by arc $\widehat{AC}$ and the angle at the center of the circle subtended by arc $\widehat{DE}$ are vertical angles.

Step2: Identify the measure of the vertical - angle

The measure of the central angle corresponding to arc $\widehat{AC}$ is $39^{\circ}$. Since vertical angles are equal, the measure of the central angle corresponding to arc $\widehat{DE}$ is also $39^{\circ}$. The measure of an arc is equal to the measure of its central angle. So the measure of $\widehat{DE}=39^{\circ}$.

Answer:

C. $39^{\circ}$