Height of cylindrical tank, h = 4.5m Radius of the circular end , r = (4.2/2)m = 2.1m (i) the lateral or curved surface area of cylindrical tank is 2πrh = 2×(22/7)×2.1×4.5 m2 = (44×0.3×4.5) m2 = 59.4 m2 Therefore, CSA of tank is 59.4 m2. (ii) Total surface area of tank = 2πr(r+h) = 2×(22/7)×2.1×(2.1+4.5) = 44×0.3×6.6 = 87.12 m2 Now, Let S m2 steel sheet be actually used in making the tank. S(1 -1/12) = 87.12 m2 This implies, S = 95.04 m2 Therefore, 95.04m2 steel was used in actual while making such a tank.