Find the lateral curved surface area of a cylindrical petrol storage tank that is 4.3 m in diameter and 4.5 m high. How much steel was actually used, if 
of steel actually used was wasted in making the closed tank?
Given,
Diameter of cylindrical tank = 4.3 m
Radius of tank = 
Height of tank = 4.5 m
Lateral curved surface area of tank = 2πrh =
m2
Let total steel used in making of tank = X m2
Wasted steel = 
m2
Actual steel used = X-
2
∴ 
=
= x = 
11