Question

A rectangular sheet of paper, $44cm\times 20cm$, is rolled along its length to form a cylinder. Find the total surface area of the cylinder thus generated.

Answer 1

Since, the sheet of paper is rolled along its length, therefore,

The circumference of the base of the cylinder so formed $=44cm$ and

Height of the cylinder $=20cm$

Now, we know that circumference of the base is $2\pi r$

Therefore,

$\Rightarrow 2\times \frac{22}{7}\times r=44$

$\Rightarrow r=44\times \frac{7}{44}=7cm$

Hence, total surface area of the cylinder $=2\pi r(r+h)$

$=2\times \frac{22}{7}\times 7(7+20)$

$=44\left(27\right)$

$=1188c{m}^2$