Sector Area

Introduction

A sector is defined as a region of a circle bounded by 2 radii and an arc.

Depending on the size of the sector, we can divide sectors into either a major sector (> semicircle) or a minor sector (< semicircle).

Formula

The area of a circle = πr2

The area of a sector is a fraction (θ out of 360°) of the area of a circle where θ is the angle subtended to the centre.

Proof for Radian Formula

Test Yourself!

Use the applet below to test your understanding of the area of a Sector.

Difficulty increases with the amount of points scored.