SOLUTION: If the surface area of a sphere is 86*pi ft^2, what is its diameter? I get 2*square root of 21.5 ft., but my answer key says the answer is the square root of 86 ft. How did they

Algebra ->  Surface-area -> SOLUTION: If the surface area of a sphere is 86*pi ft^2, what is its diameter? I get 2*square root of 21.5 ft., but my answer key says the answer is the square root of 86 ft. How did they       Log On


   

Question 23470: If the surface area of a sphere is 86*pi ft^2, what is its diameter? I get 2*square root of 21.5 ft., but my answer key says the answer is the square root of 86 ft. How did they get that?
Thanks.
Debby
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
The formula for the surface area of a sphere is:
S+=+%28pi%29D%5E2 Where D is the diameter of the sphere.
%28pi%29D%5E2+=+86%28pi%29 Divide both sides by %28pi%29
D%5E2+=+86 Take the square root of both sides.
D+=+sqrt%2886%29ft.