Circle-Scope

Angle at Center vs. Angle at Circumference

Drag points A, B, or C

Live Measurements

Angle at Center
(AOB)
--°
Angle at Arc
(ACB)
--°
∠AOB = 2 × ∠ACB
Explanation: The angle subtended by an arc at the center is double the angle subtended by it at any point on the remaining part of the circle.