Question 913608
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*pi*R^2-h*pi*r^2}}}
{{{highlight(v=(h)(pi)(R^2-r^2))}}}


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.