Question

It is required to make a closed 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?
$[Assume\pi =\frac{22}{7}]$

Answer 1

Height (h) of the cylindrical tank = 1 m
Base radius (r) of cylindrical tank$=\left(\frac{140}{2}\right)cm=70cm=0.7m$

Area of sheet required = Total surface area of the tank $=2\pi r(r+h)$
$\Rightarrow [2\times \frac{22}{7}\times 0.7(0.7+1\left)\right]m^2=(4.4\times 1.7)m^2=7.48m^2$