SOLUTION: A sphere with the diameter 5 feet is being painted. How much more paint would be needed to paint a sphere that has four times the diameter?

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Question 1033949: A sphere with the diameter 5 feet is being painted. How much more paint would be needed to paint a sphere that has four times the diameter?
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Area of sphere, 4pi%2Ar%5E2
but for diameter d=2r, area is 4pi%282d%29%5E2=highlight%2816pi%2Ad%5E2%29.


Question asks to computer -16pi%2A5%5E2%2B16pi%2A20%5E2.
16pi%28400-25%29
375%2A16pi
Finish in any way you want.

Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
A sphere with the diameter 5 feet is being painted. How much more paint would be needed to paint a sphere that has four times the diameter?
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The surface area of the larger sphere is 4%5E2 = 16 times the area of the smaller sphere.

Accordingly, the larger sphere requires 16 times the amount of paint for the smaller sphere.