Please help lateral surface area

At a sand and gravel plant, sand is falling off a conveyor and onto a conical pile at a rate of 16 cubic feet per minute. the diameter of the base of the cone is approximately three times the altitude. at what rate is the height of the pile changing when the pile is 12 feet high? (hint: the formula for the volume of a cone is v = 1 3 πr2h.)

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base