Geometry & Trigonometry
Basic

Area of a Sector

Area of a circular sector (θ in radians).

Formula

A=12r2θA = \frac{1}{2} r^2 \theta

Variables

rRadius
\thetaAngle in radians

Example

Radius 6, angle 2 rad: A = ½·6²·2 = 36 square units.

Did You Know?

A pizza slice is a sector — its area is just a fraction of the whole pie's πr².

circlesectorarea