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Volume of the cone 
Let r be the radius and h be the height of the cone \ \
\Given that diameter is same as that of height \ \
\Thus,
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Rewrite the above equation in terms of h because we need to calculate the rate of change of height \ \
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Differentiate both sides with respect to t \ \
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We need to find out
when,
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Given that 
Substitute these values in above equation \ \
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