A cylindrical piece of iron pipe is shown below. The wall of the pipe is 0.75 inch thick, and the pipe is open at both ends: The figure shows a cylinder of height 12 inches and diameter 8 inches. What is the approximate inside volume of the pipe? (8 points) 398 cubic inches
603 cubic inches
565 cubic inches
412 cubic inches

It's 398

Step-by-step explanation.

Diameter of 8.

height of 12.

8 - .75 - .75= 6.5

6.5/2 = 3.25

3.25 x 3.25 x 12 x 3.14 = 397.995

round to the nearest whole number and you get

398

Take the diameter (8) an subtract is by both sides of the walls (0.75 each wall) that gives you 6.5. Take that 6.5 and half that, because you need to have the radius to solve volume problems, giving you 3.25.  Then multiply 3.25 by 3.25 together ( I know it seems redundant but it just works easier this way) This gives you 10.5625. After that take 10.5625 then multiply it into 12, being the height, which gives you 126.75. Finally take 126.75 and multiply that into 3.14 (pie) giving you the answer.

there are no short passages to look at

8(-10x+3.5y-7)

8×-10x + 8×3.5y + 8×-7

-80x + 28y - 56

therefore

-80x+28y-56 is the correct answer