Question

The lateral or curved surface area of a closed cylindrical petrol storage tank that is $4.2$ m in diameter and $4.5$ m high.

Answer 1

Height(h) of cylindrical tank $=4.5$m

Radius(r) of the circular end of cylindrical tank $=\left(\frac{4.2}{2}\right)m=2.1m$

Curved surface area of tank $=2\pi rh$

$=(2\times \frac{22}{7}\times 2.1\times 4.5)m^2$

$=(2\times \frac{22}{7}\times \frac{21}{10}\times \frac{45}{10})m^2$

$=(22\times \frac{3}{5}\times \frac{9}{5})m^2$

$=59.4m^2$.