**Find****(i) the lateral or curved surface area of a closed cylindrical petrol storage tank that is 4.2 m in diameter and 4.5 m high.****(ii) how much steel was actually used, if of the steel actually used was wasted in making the tank.**

**Solution (i)**

Diameter of cylindrical petrol storage tank **m**

Radius of cylindrical petrol storage tank **m**

Height of cylindrical petrol storage tank **m**

**Curved Surface Area of cylindrical petrol storage tank**

**Solution (ii)**

Let total steel used

It is given that th of steel was wasted in making the tank.

Therefore, is the amount of steel wasted.

Total Surface area of cylindrical petrol storage tank

**According to the given condition, we will have**

Total surface area of cylindrical petrol storage tank