A sector of a circle is a portion of a circle enclosed by two radii and the arc between them. It resembles a "slice of pie" or a "wedge" and is commonly seen in pie charts, clocks, and engineering components involving rotation. The size of the sector depends on the central angle subtended at the center.
The area of a sector depends on the central angle and radius:
\[ A = \frac{\pi r^2 \alpha}{360} = \frac{br}{2} \]
where:
This formula calculates the curved boundary of the sector:
\[ b = \frac{2 \pi r \alpha}{360} \]
where: