Question

Find CSA of cylinder whose diameter is 4.2 and height is 5m.

Answer 1

$CSA\:of\: cylinder = 2\pi \times rh \\ \\ = 2 \times \frac{22}{7} \times \frac{4.2}{2} \times 5 \\ \\ = \frac{924}{14} = 66 \: {cm}^{2}$

Answer 2

Given,

Diameter = 4.2 cm

radius = $\frac{4.2}{2}$

= 2.1 m

h = 5 m


therefore CSA OF CYLINDER = 2πrh

$= 2 \times \frac{22}{7} \times \frac{21}{10} \times 5$

$= 66 \: {m}^{2}$