Question

a cylindrical piece of iron pipe is shown below. the wall of the pipe is 1.25 inches thick. what is the approximate inside volume of the pipe? 332 cubic inches 69 cubic inches 703 cubic inches 99 cubic inches

Explanation:

Step1: Find inner - radius

The outer diameter is 8 inches, and the wall thickness is 1.25 inches. So the inner - diameter $d = 8-(2\times1.25)=8 - 2.5 = 5.5$ inches. Then the inner - radius $r=\frac{d}{2}=\frac{5.5}{2}=2.75$ inches.

Step2: Use volume formula for cylinder

The volume formula for a cylinder is $V=\pi r^{2}h$. Given $h = 14$ inches and $r = 2.75$ inches. Substitute the values into the formula: $V=\pi\times(2.75)^{2}\times14$.
$V=\pi\times7.5625\times14\approx3.14\times7.5625\times14$.
$V\approx3.14\times105.875\approx332$ cubic inches.

Answer:

332 cubic inches