h = 3r
v = 1/3 π r^2 h = πr^3
dv/dt = 3πr^2 dr/dt
Now just plug in your numbers
A cone shaped candle whose height is 3 times its radius is melting at the constant rate of 1.4 cm^3 s^-1. If the proportion of radius to height is preserved, find the rate at which the radius will be decreasing when it is 3.7cm.
Answer: -0.01
1 answer