A great conical mound of height h is built by the slaves of an oriental moarch, to commemorate a victory over the barbarians. If the slaves simply heap up uniform material found at ground level, and if the total weight of the finished mound is M, show that the work they do is (1/4)hM.
dW = dF(distance)
W = ∫ρ*dV*(distance)*dx
The Attempt at a Solution
I said dF is equal to ρ*dV and the distance is x.
dV should be equal to ∏r2h*dx.
I just really don't know what to do from this point. What does the given M have to do with anything?