Question

A rectangular sheet of dimensions $7cm\times 6cm$ was folded along its breadth to form cylinder such that the perimeter of base of the cylinder is equal to the breath of the sheet Find the approximate volume (in $c{m}^3$) of the enclosed space

• A. $20$
• B. $22$
• C. $25$
• D. $30$

Answer 1

Answer: (A)

$20$

Given, Circumference of the base of the cylinder $=6cm$
Circumference of base of cylinder $=2\pi R$
So, $2\times \frac{22}{7}\times R=6$
$\Rightarrow R=\frac{21}{22}$ cm
Height of the cylinder will be the length of the rectangle $=7cm$
Volume of a Cylinder of Radius "$R$" and height "$h$" $=\pi R^{2}h$
Hence, volume of the given cylinder $=\frac{22}{7}\times \frac{21}{22}\times \frac{21}{22}\times 7=20.045$ or $20{cm}^3$