Answer: 85 cubic feet
Work Shown:
d = 3 = diameter
r = d/2 = 3/2 = 1.5 = radius
h = 12 = height or length of the pipe
pi = 3.14 approximately
V = volume of the cylinder pipe
V = pi*r^2*h
V = 3.14*(1.5)^2*12
V = 84.78
V = 85
The cylindrical pipe's volume is about 85 cubic feet.