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How many feet of piping can be made from 5 cubic feet of iron if the outer diameter of the pipe is 16 inches and the inner diameter is 12 inches?
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Your guiding equation is
5 = . (1)
is the volume of the cylinder of the radius 8 = inches and the length of L feet.
is the volume of the cylinder of the radius 6 = inches and the length of L feet.
The difference is the volume of the pipe, which is a hollow cylinder.
The number "5" in the left side of the equation (1) is the given volume of the iron.
Simplify (1):
5 = = ,
hence
L = .
Use your calculator.