Question 650797
Water is pouring into an inverted cone at the rate of 3.14 cubic meters per minute. The height of the cone is 10 meters, and the radius of its base is 5 meters. How fast is the water level rising when the water stands 7.5 meters above the base?
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 "when the water stands 7.5 meters above the base"  implies the point is at the top, not inverted.  r = h/2 if h is measured from the point of the cone.
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{{{V = pi*r^2h/3}}}
r = h/2
{{{V = pi*h^3/12}}}
{{{dV/dt = 3pih^2/4*(dh/dt)}}} = 3.14 m^3/min
Using the 3.14 for pi
dh/dt = 4/(3h^2) m/min
dh/dt = 4/(3*56.25) = 0.0237 meter/minute