Area of Sectors - JSS3 Mathematics Lesson Note

A sector is a portion of a circle enclosed by two radii and an arc. To find the area of a sector, you use the formula:

Area of Sector=𝜃=360∘×𝜋𝑟^2

where:

θ is the angle of the sector in degrees.

𝑟 is the radius of the circle.

Example:

Suppose we have a circle with a radius of 10 cm and a central angle of 60∘. To find the area of the sector formed by this angle:

Area of Sector=60∘/360∘×𝜋×(10 cm)^2

Area of Sector=1/6×𝜋×100

Area of Sector=100/6𝜋

Area of Sector ≈ 52.36 cm^2