It is not possible to answer the question because you have not stated which of the two given measures is the height and whether the other measure is the radius or diameter or circumference. Without these critical items of information it is impossible to give a sensible answer.
It will take 5,104.1 gallons of water to fill this cylinder.
615,142 gallons of water are needed to fill this cylinder.
587.5 US gallons Volume of a cylinder = PI * height * radius * radius 3.14159 * 4 * 2.5 * 2.5 = 78.5398 cubic feet 78.5398 (cubic feet) = 587.5185 US gallons
17,953.2 gallons
If this is a round pool 18 feet across and you fill it with 4 feet of water, it contains 7,646 gallons of water.
An 18-foot round pool with 3 feet of water contains 5,734.8 gallons of water. If you fill it to 4 feet deep it increases to 7,646 gallons of water.
It would require 2,937.6 US gallons of water to fill the pipe.
If you fill it to four feet deep, the total is 10,408 gallons of water.
A pool this size with an average depth of 16 feet requires 462,560 gallons of water to fill it to the top.
(3.5 feet) * PI * ((9 feet)^2) = 6 662.46122 US gallons
7222 cubic feet of water is equal to approximately 54,024.3 US gallons. (1 cubic foot = 7.480519481 gallons)
Three feet of water in a 12-foot round pool is about 2,550 gallons.