SOLUTION: 5m long section of concrete piping.The outer radius is 50cm and the inner radius is 45cm (a)Determine the volume of concrete in the pipe(correct to 3 decimal places)

Algebra ->  Surface-area -> SOLUTION: 5m long section of concrete piping.The outer radius is 50cm and the inner radius is 45cm (a)Determine the volume of concrete in the pipe(correct to 3 decimal places)      Log On


   

Question 913608: 5m long section of concrete piping.The outer radius is 50cm and the inner radius is 45cm
(a)Determine the volume of concrete in the pipe(correct to 3 decimal places)
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Think like these are two cylinders of same length but different diameters, but the inner cylinder is the empty part, or like the full cylinder had the inner cylinder removed.

If R=50 cm and r=45 cm, as their radii,
and if h=5 meter length, or h=500 cm length
then keeping as centimeters, v=h%2Api%2AR%5E2-h%2Api%2Ar%5E2
highlight%28v=%28h%29%28pi%29%28R%5E2-r%5E2%29%29

Just substitute the values, in cm's if you want to stay that way, and evaluate v. When using the values for the radii, you might want to take advantage of the formula for difference of two squares. That is your choice to make.