Question

A rectangular sheet of paper 44 cm x 20 cm is rolled along its length to form a cylinder. Find the volume of the cylinder so formed.

Answer 1

Given:

A rectangular sheet 44 cm × 20 cm is rolled along its length to form a cylinder.

When rolled along its length, the length 44 cm becomes the circumference of the circular base. So 2πr = 44.

Radius r = `44/(2π) = 22/π` cm.

Height of the cylinder h = 20 cm (the other side of the rectangle).

Volume V = πr²h 

= `π (22/π)^2 × 20`

= `π (484/π)^2 × 20`

= `9680/π` cm³

Using π = `22/7`

Gives r = 7 cm 

V = `22/7 × 7^2 × 20`

V = 3080 cm³