Question

A rectangular piece of paper of width 20 cm and length 44 cm is rolled along its width to form a cylinder what is the curved surface area of the cylinder so formed

Answer 1

The curved surface area of the cylinder is 880 cm².

Given data :

Length of the rectangular paper sheet = 44 cm

Width of the rectangular paper sheet = 20 cm

• Now,as the cylinder was formed by rolling the paper along it's width,then the :

Base circumference of the cylinder = width of the paper = 20 cm

Height of the cylinder = length of the paper = 44 cm

• Now,we have to calculate the curved surface area of the given cylinder by using the following mathematical formula :

Circumference of the base × Height

• So,the curved surface area of the cylinder = 20×44 = 880 cm² (answer)

Answer 2

Curved surface area of the cylinder is 880 cm²

Given:

A rectangular piece of paper of width 20 cm and length 44 cm

Rolled along width to form a cylinder

To Find:

Curved surface Area of the cylinder so formed

Solution:

Area of Rectangle = Length x Breadth

Curved surface area of cylinder = 2πrh

circumference of circle =  2πr

A rectangular piece of paper  rolled to form a cylinder

Then its curved surface area will be same as area of the sheet irrespective of the direction along which it is rolled

( As CSA = Circumference of base x height)

Circumference =  2πr , h = height

In one case circumference = 44 cm  and height = 20 cm

In another case  circumference = 20 cm  and height = 44 cm

Hence CSA of cylinder  =  20 x 44 = 880  cm²

Curved surface area of the cylinder is 880 cm²