Your formula is going to be the Volume of a cone:

V= 1/3 pi*r^2*h

since h=2r you have:

V = 2/3 pi*r^3 ..... You differentiate this with respect to time.

then you have dV/dt = 10 , and you need to find dr/dt when h=4, same thing as saying r=2.

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- October 8th 2009, 01:00 PM #1

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## Put what where?

Please help with the formula on how to solve this problem. Sand is being poured onto a conical pile at the rate of 10ft.^3/s. The conical pile's height is always twice its radius. At what rate is the radius of the pile increasing when its height is 4 feet.

- October 8th 2009, 01:20 PM #2

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- October 8th 2009, 01:24 PM #3

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- October 8th 2009, 01:26 PM #4

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