Question

From a square cardboard, a circle of biggest area was cut out. If the area of the circle is $154c{m}^2$, calculate the original area of the cardboard.

Answer 1

We have,

Area of circle $=154c{m}^2$

So,

$\pi r^2=154$

$\Rightarrow \frac{22}{7}{r}^2=154$

$\Rightarrow r^2=\frac{154\times 7}{22}$

$\Rightarrow r^2=7^2$

$\Rightarrow r=7cm.$

Length of square$=2\times 7=14cm.$

Now, Area of square

$=14\times 14$

$=196c{m}^2$

Hence, this is the answer.