SOLUTION: Hi, My husband needs to build a fuel/chemical tank for work out of a cylinder pipe. It needs to hold 15 gallons but he isn't sure what length and diameter the pipe needs to be (in

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Question 626398: Hi, My husband needs to build a fuel/chemical tank for work out of a cylinder pipe. It needs to hold 15 gallons but he isn't sure what length and diameter the pipe needs to be (in inches/feet) to achieve his goal. I am stumped on how to even find an equation for something such as this. ANY help would be greatly appreciated!! Thank you!
Answer by solver91311(24713) (Show Source):
You can put this solution on YOUR website!

15 gallons is equivalent to 3465 cubic inches (Google "15 gallons in cubic inches" if you want to check for yourself)

The number of cubic inches in a cylinder is given by:

Theoretically, there are infinite solutions to the equation:

But from a practical, real-world point of view, pipe comes in standard size diameters. So he needs to pick a diameter that he wants to use. Then he needs to follow the following steps:

1. Make sure he measures the inside diameter (ID) of the pipe.

2. Divide the pipe ID by 2 to get the radius.

3. Square the radius.

4. Multiply the squared radius by an appropriate approximation of . 3.14 should do nicely.

5. Divide 3465 by the result of step 4 and round to whatever precision makes him happy and that is the length of the pipe of the chosen diameter that he needs.

For example, let's say that he decides to use a 10" ID pipe. Half of 10 is 5. 5 squared is 25. 25 times 3.14 is 78.5. 3465 divided by 78.5 is approximately 44.14, or roughly 44 11/16 inches which is the length of 10" ID pipe he needs.

20 inch diameter pipe is 1/4 of that length.

And so on...

John

My calculator said it, I believe it, that settles it