Question

The circumference of a circle is $31.4cm$. Find the area of the circle? (Take $\pi =3.14$)

• A. $58.5c{m}^2$
• B. $48.5c{m}^2$
• C. $78.5c{m}^2$
• D. $88.5c{m}^2$

Answer 1

The correct option is C $78.5c{m}^2$

Given,

circumference of the circle$=31.4cm$

Let, the radius be $r$

$\Rightarrow 2\pi r=31.4$

$\Rightarrow r=\frac{31.4}{2\times \pi }$

$\Rightarrow r=\frac{31.4}{2\times 3.14}$

$\Rightarrow r=5$

So, the radius $r=5cm$

Now, Area of circle $=\pi r^2$

$=3.14\times (5{)}^{2}c{m}^2$

$=3.14\times 25c{m}^2$

$=78.5c{m}^2$

Hence, the area of the circle is $78.5c{m}^2$.