Question

A rectangular pipe of metal $16$ cm $\times 32$ cm rolled along its length and a cylinder is formed. Find the surface area of the cylinder. (Use $\pi =\frac{22}{7}$)

• A. $532.13c{m}^2$
• B. $542.13c{m}^2$
• C. $552.13c{m}^2$
• D. $562.13c{m}^2$

Answer 1

The correct option is B $542.13c{m}^2$

Let height, $h$ of the cylinder be $32$ cm
Circumference of the base $=2\pi r$
$2\pi r=16$
$2\times \frac{22}{7}\times r=16$
$44\times r=16\times 7$
$r=2.5$
Therefore, surface area of the cylinder = $2\pi rh+2\pi r^2$
$=2\times \frac{22}{7}\times 2.5\times 32+2\times \frac{22}{7}\times {2.5}^2$

$=502.85+39.28$
$=542.13c{m}^2$