Question

The length of the equator of the globe is $44\mathrm{cm}$. Find its surface area.

Answer 1

Calculating the surface area:

Let the radius of the globe be $r$.

The length of the equator of the globe means the circumference of the globe.

Circumference of the globe.$=44\mathrm{cm}$

$$\begin{gathered} \Rightarrow 2\mathrm{\pi }r=44 \\ \Rightarrow 2\times \frac{22}{7}\times r=44 \\ \Rightarrow r=\frac{44\times 7}{44} \\ \Rightarrow r=7\mathrm{cm} \end{gathered}$$

The surface area of the globe is computed as,

$\therefore$Surface area $=4{\mathrm{\pi r}}^2$

$$\begin{gathered} \Rightarrow =4\times \frac{22}{7}\times {\left(7\right)}^2\left[\because \mathrm{\pi }=\frac{22}{7}\right] \\ \Rightarrow =4\times 22\times 7 \\ \Rightarrow =616{\mathrm{cm}}^2 \end{gathered}$$

Hence, the surface area is $616{\mathrm{cm}}^2$.