Question

The area of a circle is 154 cm². Find the radius of the circle.

Answer 1

Let the radius of the circle be r cm.
Area of the circle (A) = 154 cm²
$$\begin{gathered} \Rightarrow 154=\frac{22}{7}\times {\left(r\right)}^2{\mathrm{cm}}^2 \\ \Rightarrow r^2=\left(\frac{154\times 7}{22}\right) \\ \Rightarrow r^2=\left(\frac{1078}{22}\right) \\ \Rightarrow r^2=\left(49\right) \\ \Rightarrow r=7\mathrm{cm}. \end{gathered}$$

Hence, the radius of the circle is 7 cm.