The graph shown represents the volume of petroleum in a spherical tank with a 15-foot radius as a function of the height of the liquid, in feet. This relationship can be modeled by the equation y = 15πx2 − πx3. What is the approximate height of the petroleum in the tank when the volume is 5,300 ft3?
12.25 ft
12.5 ft
12.75 ft
13.25 ft