Question

The circumference of a circle is 22 cm. Find its area.

Answer 1

Let r cm be the radius of the circle.
Now,
Circumference of the circle:
$$\begin{gathered} 2\mathrm{\pi }r=22 \\ \Rightarrow 2\times \frac{22}{7}\times r=22 \\ \Rightarrow r=\left(22\times \frac{7}{44}\right)\mathrm{cm} \\ \Rightarrow r=\frac{7}{2} \end{gathered}$$

Also,
Area of the circle$=\mathrm{\pi }{r}^2$
$$\begin{gathered} =\left(\frac{22}{7}\times \frac{7}{2}\times \frac{7}{2}\right){\mathrm{cm}}^2 \\ =\frac{77}{2}{\mathrm{cm}}^2 \\ =38.5{\mathrm{cm}}^2 \end{gathered}$$