Question

The circumference of a circle exceeds the diameter by $16.8cm$. Find the circumference of the circle.

Answer 1

Let the radius of the circle be $rcm$.

According to the given condition,

Circumference of a circle $=$ Diameter of a circle + $16.8$

$\therefore$ $2\pi r=2r+16.8$

$\Rightarrow$ $2\times \frac{22}{7}\times r-2r=16.8$

$\Rightarrow$ $\frac{44r-14r}{7}=16.8$

$\Rightarrow$ $\frac{30r}{7}=16.8$

$\therefore$ $r=\frac{16.8\times 7}{30}=3.92cm$

$\Rightarrow$ Circumference of a circle $=2\pi r$

$\therefore$ Circumference of a circle $=2\times \frac{22}{7}\times 3.92=24.64cm$