Central Angle of a Circle

Central Angle and Arc Length

The central angle of a circle is the angle based at the circle's center. In other words, the vertex of the angle must be at the center of the circle. A central angle is formed by two radii that start at the center and intersect the circle itself.

The middle circle in the picture below depicts a central angle because this angle's vertex rests on the center of the circle.

Interactive Arc and Central Angle

$$\overparen{\rm BC} = \class{data-angle}{56.43} \\ \angle A = \class{data-angle}{56.43}$$
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