(6/7) to the 2nd power

154 cu. in

Step-by-step explanation:

The space you have to measure is a cylinder.

Its height is the same as the height of the pipe, 16 inches.

Its diameter =inner diameter of pipe

= outer diameter of pipe - thickness of walls at each end of diameter

= 6 - 2(1.25)

= 3.5 inches

radius r = 1.75 inches

A cross-section of the cylindrical space is a circle.

area of circle = πr² = π * 1.75² = 9.625

volume = area of circle * height

9.625 * 16

= 154 cu. in.