Question

A petrol tank is a cylinder of base diameter 21 cm and length 18 cm fitted with the conical ends each of axis length 9 cm. Determine the capacity of the tank.

Answer 1

Given,

Base diameter of the cylindrical base of the petrol tank = 21 cm

So, its radius (r) = diameter/2 = 21/2 = 10.5 cm

Height of the Cylindrical portion of the tank (h₁) = 18 cm

Height of the Conical portion of the tank (h₂) = 9 cm

Now, we know that

The volume of the Cylindrical portion (V₁) = πr² h₁

V₁ = π(10.5)² 18

V₁ = 6237 cm³

The volume of the Conical portion (V₂) = 1/3 × 22/7 × r² × h₂

V₂ = 1/3 × 22/7 × 10.5² × 9

V₂ = 1039.5 cm³

Therefore, the total volume of the tank (V) = 2 x volume of a conical portion + volume of the Cylindrical portion

V = V₁ + V₂ = 2 x 1039.5 + 6237

V = 8316 cm³

So, the capacity of the tank = V = 8316 cm³ .