Question

The diameters of the ends of a frustum of a cone are 32 cm and 20 cm. If its slant height is 10 cm, then its lateral surface area is

Options

• 321 π cm²

• 300 π cm²

• 260 π cm²

• 250 π cm²

Answer 1

`r_1 = 32/2`

   `= 16 "cm"`

`r_2 = 20/2`

   ` = 10 cm`

Slant height = 10 cm

Total lateral surface area

`= pi(r_1 +r_2) l`

`=pi (16 + 10 )10`
= 260 \[\pi {cm}^2\]