Question

A rectangular paper of width 30 cm is rolled along its width and a cylinder of radius 21 cm is

formed. Find the volume of the cylinder.​

Answer 1

ANSWER:

• Volume of cylinder = 41580 cm³

GIVEN:

• Height of cylinder = 30 cm
• Radius of cylinder = 21 cm

TO FIND:

• Volume of cylinder formed.

SOLUTION:

• When the rectangular paper is rolled along its width then the width became the height of the cylinder formed.

Formula

• Volume of cylinder = πr²h

Now putting the values we get;

$= \frac{22}{7} \times 21 \times 21 \times 30 \\ \\ = 22 \times 3 \times 21 \times 30 \\ \\ = 66 \times 21 \times 30 \\ \\ = 41580 \: cm {}^{3}$

• Volume of cylinder = 41580 cm³

NOTE:

• Volume of right circular cylinder = πr²h
• Curved surface area of cylinder = 2πrh

Answer 2

$\huge\mathfrak\blue{Answer:}$

Given:

We have been given that the height of the cylinder is 30 cm and its radius is 21cm.

To Find:

We need to find the volume of cylinder.

Solution:

We know that inorder to find the volume of a cylinder we can use the formula: πr^2h.

We need to keep in mind that when the rectangular paper is rolled, its width becomes the height of the cylinder.

Now, substituting the given values, we have

πr^2h

$= > \frac{22}{7} \times 21 \times 21 \times 30$

$= > 22 \times 3 \times 21 \times 30$

$= > 66 \times 21 \times 30$

$= > 1386 \times 30$

$= > 41580 {cm}^{3}$

Hence the volume of cylinder is 41580cm^3.