Question

How to do this question

Answer 1

This is a 3 step problem. First you ignore the hole in the middle and find the volume anyways. Then you find the volume of the empty middle part. Then you can find the volume of the actual shape by subtracting them. 
area of a circle is= pi r^2
Volume with hole: 5*5*pi*8=200pi
Volume of hole= 1.5*1.5*pi*8= 18pi
Volume of doughnut = 200pi-18pi=182pi=571.769863u^3

r is the radius which is half of the diameter. 
pi is a big number but you can use 3.14
the formula for finding the volume is area of base times height. That's why i multiplied it by 8.]

I hope this helps