Question

It is required to make a closed circular cylindrical tank of height $1$ $m$ and base diameter $140$ $cm$ from a metal sheet. How many square meters of the sheet is required for the same?

Answer 1

Given:

Height $=1m$,
Diameter $=140cm$
So, radius $=\frac{140}{2}cm=70cm$ $=0.7m$

Area of sheet required $=$ Total surface area of the tank

$=2\pi r(r+h)$

$=2\times \frac{22}{7}\times 0.7(1+0.7)m^2$
$=2\times \frac{22}{7}\times 0.7\times 1.7m^2$

$=44\times 0.1\times 1.7m^2$
$=7.48m^2$

Therefore, $7.48$ square meter of sheet is required.