# A hollow garden roller, 63 cm wide with a girth of 440 cm,

Question:

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.

Solution:

Given, h = 63 cm

The outer circumference of the roller = 440 cm

Thickness of the roller = 4 cm

Let, R be the external radius

We know that,

22/7 * R = 440

2 * 22/7 * R = 440

R = 70

The thickness is given as 4cm, so the inner radius 'r' is given as

⟹ r = R - 4

⟹ 70 - 4

⟹ 66cm

Here, we know the inner and outer radii

So, the volume is given as

$\Rightarrow V=\pi\left(R^{2}-r^{2}\right) h$

$=22 / 7 *\left(70^{2}-66^{2}\right) * 63$

= 22/7 * 4 * 136 * 63

$=107712 \mathrm{~cm}^{3}$