Question

Patrick got a playing toy as his birthday present, which surprisingly had no color on it. He wanted to color it with his crayons. The toy is shaped like a cone surmounted by a hemisphere. The entire toy is 5 cm in height and the diameter of the toy is 3.5 cm. Find the surface area of the toy. Use = 3.14.

Answer 1

h = 5 cm

d = 3.5 cm

r = 3.5 cm/2

r = 1.75 cm

We need to add up the areas of each of the figures. That is a cone and a half-sphere.

For the cone

`SA=\pi\cdot r^2+\pi\cdot r\cdot l`

r = 1.75 cm

l = h - r

l = 5 - 1.75

l = 3.25 cm

`\begin{gathered} SA=3.14\cdot1.75\cdot3.25 \\ SA=8.14\text{ cm2} \end{gathered}`

For the semi-sphere

`\begin{gathered} SA=3\pi\cdot r^2 \\ SA=2\pi\cdot1.75^2 \\ SA=3\cdot3.14\cdot1.75^2 \\ SA=28.86\text{ cm2} \end{gathered}`

Total

SA1 + SA2

28.86 + 8.14

Total = 39.6 cm2