Find

(i) The lateral or curved surface area of a closed cylindrical petrol storage tank that is4.2 m in diameter and 4.5 m high.

(ii) How much steel was actually used, ifof the steel actually used was wasted in making the tank

Height (h) of cylindrical tank = 4.5 m

Radius (r) = () = 2.1 m

(i) Lateral or curved surface area of tank = 2πrh

= 2 * * 2.1 * 4.5

= (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 * * 2.1 * (2.1 + 4.5) m²

= (44 × 0.3 × 6.6) m²

= 87.12 m²

Let x m² steel sheet be actually used in making the tank

x (1 - ) = 87.12 m²

x = ( * 87.12) m²

x = 95.04 m²

Therefore, 95.04 m² steel was used in making such a tank