Question

Find the curved surface area of the frustum of a cone, the diameters of whose circular ends are 20 m and 6 m and its height is 24 m.

Answer 1

Here, h = 24 m

r₁ = `20/2` = 10 m

r₂ = `6/2` = 3 m

Slant height `(l) = sqrt(((r_1 - r_2)^2 + h^2))`

= `sqrt(((10 - 3)^2 + (24)^2)` 

= `sqrt(625)`

= 25 m

CSA = π(r₁ + r₂)l

= `22/7 (10 + 3)25`

= `22/7 xx 13 xx 25`

= `7150/7`

= 1021.42 m²