# Central Angle

- Author:
- acastagna

- Topic:
- Geometry

## Definition of Central Angle

A central angle is an angle whose vertex is the center of a circle, and whose sides are radii.

## Central Angle Theorem

The measure of a central angle is always equal to the degree measure of the intercepted arc. In the figure below, m A = m arc BC

## Try It !

Drag points C and D to change the measure of the central angle and the arc. Look at the relationship between the angle A and arc CD.

## Try These Questions

PQR is a central angle that measures 42, what is the measure of arc PR ?

In circle O, arc FG measures 84, what is the measure of arc FOG ?