Question

The surface area of a sphere is 394.24 cm². Find its radius and volume.

Answer 1

Surface area = 394.24 m²
Suppose that r cm is the radius of the sphere.

$$\begin{gathered} \mathrm{Then}4\mathrm{\pi }{r}^2=394.24 \\ \Rightarrow r^2=\frac{394.24\times 7}{4\times 22}=31.36 \\ \Rightarrow r=5.6\mathrm{m} \end{gathered}$$

$$\begin{gathered} \therefore \mathrm{Volume}\mathrm{of}\mathrm{the}\mathrm{sphere}=\frac{4}{3}{\mathrm{\pi r}}^3 \\ =\frac{4}{3}\times \frac{22}{7}\times 5.6\times 5.6\times 5.6 \\ =735.91{\mathrm{m}}^3 \end{gathered}$$