Question

A hollow garden roller of 42 cm diameter and length 152cm is made of cast iron 2cm thick . Find the volume of iron used in the roller. Please send answer its urgent

Answer 1

In the attachments I have answered this problem.

Clearly the garden roller is in the form of hollow cylinder .

The following letters are used to denote the dimensions of the cylinder:

R- outer radius

r - inner radius

h - height

See the attachment for detailed solution.

Answer 2

Formula used:
Volume of Cylinder =
$\pi {r}^{2} h \: {unit}^{3}$
given : Diameter = 42 cm

radius = 21 cm

height/length = 152 cm

External volume of garden roller

=
$\frac{22}{7} \times 21 \times 21 \times 152 \: {cm}^{3} \\ \\ = 22 \times 63 \times 152 \: \: {cm}^{3} \\ \\ = 210672 \: {cm}^{3}$
Thickness of Iron sheet 2 cm

Internal Radius = 19 cm

Internal Volume of garden roller

=
$\frac{22}{7} \times 19 \times 19 \times 152 \\ \\ = 172454.85 \: {cm}^{3}$

Volume of iron used = External volume - Internal volume

= 210672 - 172454.85 cm-cube

= 38217.15 cm-cube