You didn't provide enough information to fully answer this question. Volume requires 3 dimensions, and you provided 2 (or didn't fully explain the 3rd). To determine volume, you need length, width and height LxWxH=Volume. I'll explain how to solve this math problem the best way I can. 1 gallon = 231 cubic inches http://www.onlineconversion.com/volume.htm Now that you know there are 231 cubic inches per gallon, determine the volume of water you need in inches. I'm going to guess you were meaning the tube is 12 inches long and either a 4 inch diameter. Volume of a cylinder can be acheived by multipling the area of the base times height. Assuming your cylinder is a perfect circle with an inside diameter of 4 inches, the base would be PI * r2 or 3.141592 * (2*2) or 12.535668 inches square. Multiply this times the height (12), and you'll get the cubic inches required to fill the cylinder...or 150.796416 cubic inches. Divide by 231 (cubic inches per gallon) equalling .6528 US gallons required to fill the tube.
615,142 gallons of water are needed to fill this cylinder.
10 gallons of water are needed.
2,005 gallons of water are needed.
16 and 7/8
Round Pool: Depth x Diameter-squared x 5.9 = Volume in Gallons
It would require 2,937.6 US gallons of water to fill the pipe.
You will need a maximum of 11,230 gallons of water.
It requires 73 gallons of water to fill a 6 inch x 50 foot hose
Approximately 26,802,130 US gallons.
Exactly 5264.1669 gallons
4178 US gallons, approx.