How many gallons of water are there in a pool that is 18 feet round by 4 feet deep?

Answer 1

If you mean 18 feet in circumference (around the outside measurement) Circumference = pi x D , 18 = pi x D , Diameter = 5.730 feet
Area = pi x r squared, Area = pi x 2.865 squared , Area = 25.787 sq. feet
Volume - 25.787 x 4 = 103.148 cu. ft. x 7.48 = 771.5 gallons If you mean 18 feet across (diameter)

Area = pi x r squared, Area = pi x 9 squared , Area = 254.47 sq. feet
Volume - 254.47 x 4 = 1017.88 cu. ft. x 7.48 = 7614 gallons