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

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

knov · Answer

area=pi*radius^2 is the formula.

anonymous · Answer

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

anonymous · Answer

Are you sure D. isn't 400?

anonymous · Answer

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

knov · Answer

i thinks the answers are not correctly written.

anonymous · Answer

That's what I think.

dayakar · Answer

A = pi * d^2/4
  = pi* 40* 40 /4

  = 400 8pi

dayakar · Answer

sorry
 A= pi* 400