Help please easy detailed explanation would be nice (calculus)

-8- Part VI: Find the Rate of Change of the following function (10 points) 1 1) At a sand and gravel plant, sand is falling off a conveyor and onto a conical pile at a rate of 12 cubic feet per minute. The diameter of the base of the cone is approximately 4 times the altitude. At what rate is the height of the pile changing when the pile is 18 feet high? Express your answer in terms of it (V = WIP Trzh)