Question

Which expression can be used to find the area of a circle with a diameter of 40 cm?

A.
π · 20

B.
π · 40

C.
π · 202

D.
π · 402

Answer 1

area=pi*radius^2 is the formula.

Answer 2

Okay, so before we answer this question we should probably understand the formula to find the area of a circle. I'll cheat for ya', it's r^2 x pi. The diameter is twice the radius, so the radius is 20. 20^2 = 400. I'd think the answer is 400 x pi but... o.O

Answer 3

Are you sure D. isn't 400?

Answer 4

I don't think it's any of them...

Answer 5

i thinks the answers are not correctly written.

Answer 6

That's what I think.

Answer 7

A = pi * d^2/4
= pi* 40* 40 /4

= 400 8pi

Answer 8

sorry
A= pi* 400