The capacity of a closed cylindrical vessel of height 1 m is 15.4 litres. How many square metres of metal sheet would be needed to make it?
Given,
Volume of cylindrical vessel = 15.4 litre = 15400 cm3
Height of vessel = 1 m = 100 cm
= πr2h = 15400
= r2 = 
= r = 
Area of metal sheet required = 2πr(h+r)
= 
5