Question

what is the measure of $widehat{ab}$ in $odot o$ below? a. $100^{circ}$ b. $260^{circ}$ c. $280^{circ}$ d. $80^{circ}$

Explanation:

Step1: Recall arc - central angle relationship

The measure of an arc of a circle is equal to the measure of its central angle when the arc is subtended by the central angle.

Step2: Identify the central angle

The central angle $\angle AOB = 100^{\circ}$, and the arc $\widehat{AB}$ is subtended by $\angle AOB$. So the measure of $\widehat{AB}$ is $100^{\circ}$.

Answer:

A. 100°