Calculating the area of a circle

The area of a circle is the amount of space that is covered by the circle. It is calculated using the formula seen below:

Area of a circle = π r²

The formula is read pi r squared. The value of pi is about 3.14 and r is the radius if the circle. r² means we must multiply the radius by itself.

Example 1

If a circle has a radius of 5 meters, what is the area of that circle?

Working

Area = π r² = 3.14 x 5² = 3.14 x 25 = 78.5 square meters or 78.5 m²

Example 2

What is the area of a circle if its radius is 15 cm?

Working

Area = π r² = 3.14 x 15² = 3.14 x 225 = 706.5 cm²

Example 3

The radius of a circle is 2 feet. What is the area of the circle?

Working

Area = π r² = 3.14 x 2² = 3.14 x 4 = 12.56 square feet