Question
Find the radius of a circle whose area is $616 cm^2$.
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Answer
Let the radius of the circle be r cm
Area $=(\pi\text{r}^2)\text{cm}^2$
$\pi\text{r}^2=616$
$\Rightarrow\frac{22}{7}\times\text{r}\times\text{r}=616$
$\Rightarrow\text{r}^2=\Big(\frac{616\times7}{22}\Big)=196$
$\Rightarrow\text{r}=\sqrt{196}=14\text{cm}$
Hence, the radius of he given circle is 14cm.
Area $=(\pi\text{r}^2)\text{cm}^2$
$\pi\text{r}^2=616$
$\Rightarrow\frac{22}{7}\times\text{r}\times\text{r}=616$
$\Rightarrow\text{r}^2=\Big(\frac{616\times7}{22}\Big)=196$
$\Rightarrow\text{r}=\sqrt{196}=14\text{cm}$
Hence, the radius of he given circle is 14cm.
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