Question

If the area of a circle is 50.24 m², find its circumference.

Answer 1

We have :
Area of the circle (A) = ​${\mathrm{\pi r}}^2$ = 50.24 m²
$$\begin{gathered} \Rightarrow 50.24{\mathrm{m}}^2=\frac{22}{7}\times {\left(r\right)}^2 \\ \Rightarrow r^2=\left(\frac{50.24\times 7}{22}\right){\mathrm{m}}^2=\left(\frac{351.68}{22}\right){\mathrm{m}}^2=15.985{\mathrm{m}}^2 \\ \Rightarrow r=3.998\mathrm{m}. \end{gathered}$$

Circumference of circle (C) = $2\mathrm{\pi r}$
$$\begin{gathered} \Rightarrow C=\left(2\times \frac{22}{7}\mathrm{x}3.998\right)\mathrm{m} \\ \Rightarrow C=\left(44\times 0.571\right)\mathrm{m}=25.12\mathrm{m}. \end{gathered}$$