Question

solve this question step by step​

Answer 1

let the side of a paper be A

after rolling the perimeter of the base is 2πr

as we know,

$a = 2 \times \pi \times r$

and by que,

$\frac{r}{a} = \frac{1}{2\pi}$

so,the ratio is 1:2π

option (a) is correct

Answer 2

Given :

• Square sheet is rolled along its length to form cylinder

To find :

Ratio of base radius of cylinder to side of square

Solution :

Let -

1. Side of square = x
2. Radius of base of cylinder = r

Now, we are given that Square sheet is rolled along its length to form cylinder,

It means , side of square = Circumference of base of cylinder

$\sf \implies\: x = 2\pi r \\ \\ \sf \implies\: r \: = \dfrac{x}{2\pi}$

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➝ Radius of base of cylinder : side of square

$\sf \implies \: r : x \\ \\ \sf \implies \: \dfrac{x}{2\pi} : x \\ \\ \sf \implies \: 1 : 2\pi$

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ANSWER :

Option a) 1 : 2π