Find 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.

Radius of cylindrical petrol storage tank r = 4.2/2 = 2.1 m and height h = 4.5 m.
Curved surface area of cylindrical petrol storage tank = 2πrh
= 2 × 22/7 × 2.1 × 4.5 = 2 × 22 × 0.3 × 4.5 = 59.4 m²
Hence, the curved surface area of cylindrical petrol storage tank is 59.4 m².