Measuring the capacity of a tank

The gallon capacity of an aquarium can be found by multiplying in feet the length x width x height x 6 1/4 . For example, an aquarium 2 ft x 1 ft x 1 ft holds 12 1/2 gallons. One gallon of water has 90,000 drops, weighs 10 Ibs and exerts pressure on the inside of the aquarium glass of 10 lbs per square inch. (All figures are approximate).