A9cm wife cross section pipe has a height of 13cm . what is the volume of the pipe

I think you meant "wide." :) Since it is a pipe, you should know that it is the shape of a cylinder. Therefore, the formula would be: πr^2h. Substitute the height for h. (π(4.5)^2(13). Since it's 9 cm wide total, divide it by 2 to get the radius (part of formula), which is 4.5 So multiply π times 4.5^2 (which equals 20.25) times 13. This all will equal 826.605. You can simplify this decimal to 827. Therefore, the volume is 827 cm^3.