Subtended angle

In geometry, an angle is subtended by an arc, line segment, or any other section of a curve when its two rays pass through the endpoints of that arc, line segment, or curve section. Conversely, the arc, line segment or curve section confined within the rays of an angle is regarded as the corresponding subtension of that angle. It is also sometimes said that an arc is intercepted or enclosed by that angle.

Example of the angles subtended by an arc from two points

The precise meaning varies with context. For example, one may speak of the angle subtended by an arc of a circle when the angle's vertex is the centre of the circle.

See also

• Central angle
• Inscribed angle

External links

• Definition of subtended angle, mathisfun.com, with interactive applet
• How an object subtends an angle, Math Open Reference, with interactive applet
• Angle definition pages, Math Open Reference, with interactive applets that are also useful in a classroom setting.