Algebra Please Help, thanks if you do

Can someone check if i did this correct. it’s number 4 if you’re wondering.

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min

Suppose that 15 inches of wire cost 60 cents. at the same rate, how much (in cents) will 12 inches of wire cost