relaited rates
posted by :) .
A spherical balloon is being inflated so that its volume is increasing at the rate of 5 cubic meter per minute.At what rate is the radius increasing when the radius is 6 meters?

V = (4/3) pi r^3
dV/dt = 4 pi r^2 dr/dt = surface area * dr/dt of course
so
dr/dt = dV/dt /(4 pi r^2)
= 5/(100 pi ) = 1/(20 pi) 
thank you so much! :)

uhm, just one more thing. Isn't it 5/144π ? :)

yes, right, forgot 6 and not 5

thank you. :) you really did a big help. Godbless
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