(Q3).A toy is in the form of a cone mounted on a hemisphere. The diameter of the base and the height of the cone are 6 cm and 4 cm respectively. Determine the surface area of the toy. (Use π = 3.14)

Answer:

4 cm6 cm

Diameter of the base of the cone d = 6 cm.

∴ Radius of the base of the cone

r =
d
2
 =
= cm

Height of the cone = h = 4 cm

Slant height of the cone l = √(r2+h2)

= √(+)

= √( + )

√()

= cm

∴ C.S.A of the cone = πrl

=
× ×
=
cm2
Radius of the hemisphere =
d
2
 =
= cm

C.S.A. of the hemisphere = 2πr2

= ×
× ×
=

Hence the surface area of the toy = C.S.A. of cone + C.S.A. of hemisphere

=
+

=
≃ cm2.