Question 162480
U.S. liquid gallon is legally defined as 231 cubic inches.
.
Convert the height to inches:
20 feet = 20*12= 240 inches
and,
since diameter = 36 inches:
radius = 1/2 (diameter) = 18 inches
.
area of bottom of well = (pi)r^2 = (pi)18^2 = 1017.87 square inches
volume = "area of bottom" * height = 1017.87 * 240 = 244290.24 cubic inches
.
# of gals in well = "volume of well"/"volume of 1 gal of water"
# of gals in well = 244290.24/231 = 1057.53 gallons