Question

5. A rectangular paper 22cm x 8 cm is formed in to a cylinder by rolling along its length and find the radius of Cylinder​

Answer 1

Given:

• Dimensions of the rectangular sheet of paper = 22 cm × 8 cm

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To find:

• Radius of the cylinder formed by rolling the rectangular sheet of paper along its length.

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Solution:

Here, as the rectangular sheet of paper is rolled into a cylinder, then the height of the cylinder is equal to the breadth of the rectangle.

So,

Height of cylinder = 8 cm

Now, we are given that the sheet of paper is rolled along its length to make a cylinder. Therefore, the circumference of the circular bases of the cylinder is equal to that of the length of the rectangle.

So,

Circumference of the circular base of the cylinder = 22 cm

Now,

We know that,

Circumference of circle = 2πr

Substitute the values,

22 = 2πr

22 = 2×3.14r

$\sf \dfrac{ \cancel{ 22}}{ \cancel{ 2}\times 3.14} = r$

$\sf \dfrac{ 11}{ 3.14} = r$

$\boxed {\mathfrak {\red {3.5\ cm = radius}}}$

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Radius of the cylinder:

Radius of the cylinder is 3.5 cm.