Question

The radii of the circular ends of a solid frustum of a cone are 33 cm and 27 cm and its slant height is 10 cm. Find its total surface area. [Use π = 3.14.]

Answer 1

Greater radius = R = 33 cm

Smaller radius = r = 27 cm

Slant height = l = 10 cm

Surface area of the frustum

= πR² + πr² + πl (R + r)

= π [R² + r² + l (R+r)]

= [33² + 27² + 10(33 + 27)]π

= [1089 + 729 + 10(60)] π

= 2418 × 3.14

= 7592.52 cm²