Question

A fez, the cap used by the Turks, is shaped like the frustum of a cone (see the figure given below). If its radius on the open side is 10 cm, radius at the upper base is 4 cm and its slant height is 15 cm, find the area of material use for making it.  [use π=22/7]

Answer 1

Radius (r₂) at upper circular end = 4 cm

Radius (r₁) at lower circular end = 10 cm

Slant height (l) of frustum = 15 cm

Area of material used for making the fez = CSA of frustum + Area of upper circular end

`= pi(r_1+r_2)l + pir_2^2`

= π (10 + 4) 15 + π (4)²

= π (14) 15 + 16 π

`= 210pi + 16pi = (226xx22)/7`

`= 710 2/7 cm^2`

Therefore, the area of material used for making it is `710 2/7 cm^2`