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 are required for the same?
It is given that
Diameter of the cylinder $$=140 cm$$
Radius of the cylinder $$=\dfrac{140}{2}=70 cm$$
Height of the cylinder $$=1m=100 cm$$
We know that
Area of sheet required $$=2\times \dfrac{22}{7}\times 70 (100+70)$$
On further calculation
Area of sheet required $$=2\times \dfrac{22}{7}\times 10\times 170$$
So we get
Area of sheet required $$=74800\ cm^2= 7.48\ m^2$$
Therefore, the area of sheet required is $$7.48\ m^2$$.