A hollow garden roller 63 cm wide with a girth of 440 cm, is made of 4 cm thick iron. Find the volume of the iron.
Given,
Width of hollow cylinder = 63 cm
Girth (perimeter) = 440 cm
Let external radius of cylinder = R cm
So, 2πr = 440
= R = 
= inner radius = outer radius – thickness = 70 – 4 = 66 cm
∴ volume of iron = π( R2-r2)h = 
7