assuming you mean an 8 inch pipe....
area =Pi r 2.
4*4=16
16*3.14= 50.24 x 120 inches =6028.8 cubic inches
231 cubic inches per gallon.
6028.8/231= 26.0987 gallons
This pipe will hold 1,468.8 gallons of water.
That depends on how long the pipe is.
146.9 gallons of water.
A 16" by 1,960' pipe holds 20,471.7 gallons water.
280 gallons of water.
111 gallons of water.
14.7 gallons of water.
An 8" x 1,300' pipe holds 3,394.5 gallons of water.
There need not be any water at all in the pipe. The capacity of the pipe is approx 3.4 Imperial gallons.
6.5 US gallons of water.
1.6 gallons of water.
Up to 1,795.2 gallons of water.