Question

A rectangular piece of paper of width 20cm and length 44cm is rolled along its width to form a cylinder. What is the curved surface area of the cylinder so formed? Also find its volume.​ (please explain step by step)​

Answer 1

$\huge\sf\star$ Concept

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Given :

• A rectangular piece of paper with :
• width = 20cm
• Length = 44 cm

To Find :

• curved surface area of cylinder formed by rectangular piece of paper

Solution

$\rightarrow$ When rolled along its width then the height of the cylinder = 20cm.

$\rightarrow$ circumference of cross section = 44 cm

Let,

$\rightarrow$ The radius of the cross section be x

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According to the question

$\sf\huge\implies$ circumference of circle = 2πr

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$\sf\huge\star$ Calculations

$\sf\huge\implies$ 44cm = 2 $\times$ $\frac{22}{7}$ $\times$ x

$\sf\huge\implies$ $\frac{44×7}{44}$ = x

$\sf\huge\implies$ x = 7cm

$\therefore$ Radius = 7cm

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$\huge\sf\star$Solution:

$\sf\huge\implies$ Curved surface area = 2πrh

$\sf\huge\implies$ 2 × $\frac{22}{7}$ × 7 × 20

$\sf\huge\implies$ 880cm²

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Final answer :- 880cm²

Answer 2

Answer:

When rolled along its width the height of cylinder= 20 cm

circumference of cross-section=44cm

Let the radius of cross-section be x

A/Q

circumference of circle= 2πr

44cm=