Question

a steel company uses old steel and straps for making a closed cylindrical petrol storage tank of 4.2 m diameter and 4.5m height. find its curved surface area. if 1/2 of the steel was wasted , then how much steel is actually used in msking the tank . wich value is depicted by company? (use π=22/7)

Answer 1

radius = 4.2/2=2.1 m.  height = 4.5 m
cylindrical tank CSA :  2 * 22/7 * 2.1 * 4.5 = 59.4 m²
Total surface area = 59.4 + 2 * 22/7 * 2.1² = 87.12 m²

Since 50% (or 1/2) of the steel used was wasted, the total amount of steel actually used = 87.12 * 3/2  = 130.68 m²