Question

What is the approximate area of a circle with a diameter of 18 in?

OA. 56.5 in²
OB. 28.3 in2
OC. 254 in²
OD. 1018 in²

Answer 1

Area of a circle:
`\pi r^2`

We need to find the radius of the circle before we can find the area. The radius of a circle is half of the diameter. We are already given the diameter, so the radius would be 1/2d, where d = diameter.

Plug in 18 for d
`\implies (1)/(2) (18) = 9`.

The radius of this circle is 9 inches. Now we can plug in 9 for r in the formula for area of a circle.

`\pi 9^2 = 254.34` (rounded to the nearest whole)

The area of the circle is 254 in².