Question 796224
External volume = Pi*r^2*h 
External volume = Pi*10^2*500
External volume = 157079.63 cm^3
Inner volume = Pi*r^2*h
Inner volume = Pi*7^2*500
Inner volume = 76969.02 cm^3
External volume - Inner volume 
157079.63 - 76969.02
= 80110.61 cm^3
Hope this helps.
;-)