Question:
A toy is in the form of a cone mounted on a hemisphere with the same radius. The diameter of the base of the conical portion is 6 cm and its height is 4 cm. Determine the surface area of the toy. (Use π = 3.14)
Solution:
Radius of hemisphere and the cone are the same.
So, r = 3 cm
Surface area of the cone
$=\pi r l$
$=3.14 \times 3 \times \sqrt{3^{2}+4^{2}}$
$=47.1 \mathrm{~cm}^{2}$
Surface area of the hemisphere
$=2 \pi r^{2}$
$=2 \times 3.14 \times 9$
$=56.52 \mathrm{~cm}^{2}$
Total surface area of the toy = Surface area of the cone + surface area of the hemisphere
=47.1 + 56.52 cm2
=103.62 cm2