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 metres of the sheet are required for the same?

Given :
height(h) of the cylindrical tank = 1m
Base radius(r) of cylindrical tank
=( \(\frac{140}{2}\) )cm = 70 cm = 0.7 m

Now, Area of sheet required = total surface of tank

But, we know that,
Area of sheet required
= \(2{\pi}r(r + h)\) \({m}^2\)
= \(2 × \frac{22}{7} × 0.7(0.7 + 1)\) \({m}^2\)
= \(4.4 × 1.7\) \({m}^2\)
= 7.48 \({m}^2\)

Therefore , it will required 7.48 \({m}^2\) area of sheet.