Question

A closed cylindrical tank of radius 7 𝑚 and height 3 𝑚 is made from a sheet of metal. How much sheet of metal is required?

Answer 1

Given, the radius of the cylindrical tank, $r=7m$
Height of the cylindrical tank, $h=3m$
Total surface area of the cylindrical tank $=2\pi r(h+r)$
$=[2\times \frac{22}{7}\times 7\times (3+7\left)\right]m^2$
$=(44\times 10)m^2$
$=440m^2$

Hence, $440m^2$of metal sheet is required.