Question

What is the area of this circle? (Express your answer using π.)
(Note: The diameter is 10ft.)

Answer 1

Area of a circle is:

A = pi * r^2

If the diameter is 10 feet, the radius will be half of that or 5.

So:

A = 3.14 * 5^2

Simplify exponent:

A = 3.14 * 25

Multiply:

A = 78.5

Answer 2

The area is πr².
The radius r is half the diameter. The diameter is 10 ft so the radius is 5 ft.

$A=\pi \times 5^2=25 \pi$

The area is 25π ft².