Sector

$[asy]size(150); real angle1=30, angle2=100; pair O=origin, A=dir(angle2), B=dir(angle1); path sector=O--B--arc(O,1,angle1,angle2)--A--cycle; fill(sector,gray(0.9)); D(unitcircle); D(A--O--B); MP("O",D(O),SSW); MP("A",D(A),NNW); MP("B",D(B),NE); MP("\theta",(0.075,0.075),N);[/asy]$

A sector of a circle $O$ is a region bounded by two radii of the circle, $OA$ and $OB$ , and the arc $AB$ .

Area

The area of a sector $AOB$ is found by multiplying the area of circle $O$ by $\frac{\theta}{2\pi}$ , where $\theta$ is the central angle, $\angle AOB$ , in radians.