Question

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 $\pi =3.14$]

• A. $121.98c{m}^2$
• B. $131.88c{m}^2$
• C. $331.88c{m}^2$
• D. $531.88c{m}^2$

Answer 1

The correct option is B $131.88c{m}^2$

Surface Area of a cone = $\pi \times r(r+\sqrt{r^2+h^2})$

$⟹3.14\times 3(3+\sqrt{9+16})$

$⟹3.14\times 3(3+5)$

$⟹3.14\times 3\times 8$

$⟹75.36$

Surface area of hemisphere = $2\pi r^2$

$⟹2\times 3.14\times 3^2$

$⟹18\times 3.14$

$⟹56.52$

Total surface area of the toy = $75.36+56.52=131.88c{m}^2$