Unfortunately your question cannot be answered without an additional measurement. A gallon is actually a volume of liquid. The measurement you gave is an area related measurement.
The volume of a 100-foot diameter x 200-foot long cylinder is: 11,750,400 US gallons.
138 Imperial gallons, approx.
Do you mean a cylinder with a diameter of 5 feet and length of 12 feet? This would hold about 235.6 cubic feet or 1762.5 gallons
1.5x4x6x7.48 gallons/cubic foot=269.28 us gallons
This cylinder will hold up to 19.65 gallons of water.
A 2 ft wide pipe, 1 foot long, will contain 23.5 gallons (US).A 2 ft wide pipe, 1 foot long, will contain 23.5 gallons (US).A 2 ft wide pipe, 1 foot long, will contain 23.5 gallons (US).A 2 ft wide pipe, 1 foot long, will contain 23.5 gallons (US).
This cylinder has a volume of 3.3 US gallons or 2.75 Imperial gallons.
The cylinder holds up to 7,943.23 gallons of water.
598 Imperial gallons, approx.
36 cubic feet of water at 6.229 gallons/ cu ft = 224.2 gallons
615,142 gallons of water are needed to fill this cylinder.
A 10 foot long by 4 foot wide cylinder has volume of 126 cubic feet.