A circular sector or circle sector, is the portion of a disk enclosed by two radii and an arc, where the smaller area is known as the minor sector and the larger being the major sector. In the diagram, θ is the central angle in radians, Failed to parse (Missing texvc executable; please see math/README to configure.): r

A sector with the central angle of 180° is called a semicircle. Sectors with other central angles are sometimes given special names, these include quadrants (90°), sextants (60°) and octants (45°).

The angle formed by connecting the endpoints of the arc to any point on the circumference that is not in the sector is equal to half the central angle.

The total area of a circle is Failed to parse (Missing texvc executable; please see math/README to configure.): \pi r^2 . The area of the sector can be obtained by multiplying the circle's area by the ratio of the angle and Failed to parse (Missing texvc executable; please see math/README to configure.): 2 \pi

Another approach is to consider this area as the result of the following integral :