Sand is falling into a cone whose height is always 1/2 the diameter of the base. If the sand is falling at a rate of 1/2 cubic meters per min. How fast is the height increasin when the pile is 3 meters high? so far i've drawn my diagram and got this far. Given: h = 1/2 the base dv/dt = +1/2m3/min Needs: dh/dt the equation i was going to use is V = 1/12pih3 then i get dv/dt = (1/2pi)(3h2)dh/dt i dont know how to get the h? any help?