Question

The diameter of a circle is 40 m. What is the area of the circle in terms of `pi`?

Answer 1

1256.64 `m^2`

Explanation:

Diameter = 2 radius
40 = 2r
r = 20 meters
Area of a circle = `A=pi*r^2`
`A=pi*(20)^2`
=1256.64 `m^2`

Answer 2

`A=pi*400`

Explanation:

The area of a circle is equal to `pi*r^2`.

If your diameter is 40m, then your radius must be 20m, as the radius of a circle is always half of the diameter. With this equation, you need to multiply `pi` by `20^2`. Since `20^2 = 400`, your equation will be `pi*400`, or `pi400`.