The slant height of a frustum of a cone is 4 cm and the perimeters (circumference) of its circular ends are 18 cm and 6 cm. Find the curved surface area of the frustum(in cm2).
48cm2
Slant height of a frustum of a cone =
l = 4 cm
Perimeter of its first circular end =
18 cm
Perimeter of its second circular end =
6 cm
Curved Surface Area of frustum of the cone
=π.(r1+r2)l
=(π.r1+π.r2)l
=(2π.r1+2π.r2)l2
=(18+6)42=48cm2