calculate water volume in a pipe

[Ross]

If I have a pipe which is 4" in diamter and the pipe is 30' in length,
what is the water volume in gallons inside the pipe?

[Guest]

About 19.6 gallons

30' = 360 inches

V = (pi/4)*d*d*h
where d is INSIDE diameter of the pipe, and h the length
This will be in cu inches (the reason for converting the length.

Then 1 US gallon = 231 cu in.

[Ross]

About 19.6 gallons

30' = 360 inches

V = (pi/4)*d*d*h
where d is INSIDE diameter of the pipe, and h the length
This will be in cu inches (the reason for converting the length.

Then 1 US gallon = 231 cu in.

I should read this as pi divided by 4 X d X d X height
which two diamters do you refer too?

[Guest]

The diameter needs to be squared. I didn't have a good way to do a superscript (or I was too lazy to fire up Character Map).

I had the same problem with how to express pi = 3.14159..., but you need the constant pi/4.

Maybe V = 0.785*h*d^2 is clearer.