Question

A drinking glass is in the shape of a frustum of a cone of height 14 cm. The diameters of its two circular ends are 4 cm and 2 cm. Find the capacity of the glass.  [use π=22/7]

Answer 1

Radius (r₁) of upper base of glass =  4/2 = 2 cm

Radius (r₂) of lower base of glass = 2/2 = 1 cm

Capacity of glass = Volume of frustum of cone

`= 1/3pih = (r_1^2+r_2^2+r_1r_2)`

`=1/3pih[(2)^2 +(1)^2+(2)(1)]`

`=1/3xx22/7xx14[4+1+2]`

= 308/3 = 102 2/3 cm³

Therefore, the capacity of the glass is 102 2/3 cm³