Central angle

A central angle is an angle whose vertex is at the center of a circle and whose sides are radii. Its measure equals the measure of the arc it intercepts.

Circle: A plane curve whose points are all equally distant from a fixed center. A central angle is defined by its position within this geometric figure.
Inscribed angle: An angle whose vertex lies on a circle and whose sides are chords. It intercepts an arc like a central angle, but measures half as much.
Sector area: The area of a circular sector, proportional to its central angle. Its formula uses the angle as a fraction of a full turn.
Circumferential angle: An angle whose vertex lies on a circle and whose sides are chords. Unlike a central angle, its vertex is on the circumference.
Radius: A line segment from the center of a circle to a point on its circumference. Each side of a central angle lies along a radius.
Arc measure: The angular measure assigned to an arc, usually in degrees or radians. For a central angle, the intercepted arc has the same degree measure.
Circular segment: A region of a disk bounded by a chord and its corresponding arc. Its area can be found by subtracting a triangle from the sector set by the angle.
Tangent-chord angle: An angle formed by a tangent and a chord meeting at a point on a circle. Its vertex lies on the circle, and its intercepted arc determines a half-arc measure.
Angle: A figure formed by two rays sharing a common endpoint. A central angle is a specific kind of angle distinguished by its vertex.
Sector: A region of a disk bounded by two radii and the arc between them. The angle's sides and intercepted arc enclose this wedge-shaped region.

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