Question

The diameter and the height of a cylindrical petrol Storage tank 4.2 M and 4.5 M respectively.find it's curved surface area. How much steel was actually used if 1/12th of the steel was wasted in making the tank

Answer 1

Diameter of cylinder = d = 2r = 4.2 m
r = 2.1 m
Height of the cylinder = 4.5 m
Lateral surface area of cylinder = 2πrh
= 2 x 22 / 7 x 2.1 x 4.5
= 59.4 m2
Total surface area of cylinder = 2πr (r+h)
= 2 x 22 / 7 x 2.1 (2.1+ 4.5)
= 2 x 22 / 7 x 2.1 x (6.6)
= 87.12 m2
∴ 87.12 m2 steel was actullay used.