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 ?