9" of oil in a 275 gallon 36" round tank? How many gallons?

IF the tank is standing on end Volume = Pi (3.14) x r^2 (r = radius = 1/2 diameter) x heighth.  Diameter = 36" divide that by 2, square that number, multiply x pi, and then by 9" to find volume in cubic inches.  1 gallon = 231 cubic inches so divide by 231 to convert to gallons.