A hollow garden roller, 63cm wide with a girth of 440 cm, is made of 4 cm thick iron. Find the volume of the iron.

Explanation

The outer circumference of the roller `= 440 cm `
Thickness of the roller `= 4 cm `and
Its height `(h) = 63 cm `
Let ‘R’ be the external radius and `r` be the inner radius of the roller.
Circumference of roller `= 2 pi R = 440 `
Or `2 pi R = 440 `
`2 xx 22/7 xx R = 440`
or `R = 70 `
And, inner radius `r` is given as
`⇒ r = R – 4 `
`⇒ r = 70 – 4 `
`⇒ r = 66 `
Inner radius is `66 cm`
Now, volume of the iron is given as ` V = pi (R^2−r^2)h `
`V = 22/7(702−662)63 `
`V = 107712 `
Therefore, required volume is `107712 cm^3`.