Question

Find the radius of a circle whose circumference is 57.2 cm.

Answer 1

Circumference of the given circle = 57.2 cm
∴ C = 57.2 cm
Let the radius of the given circle be r cm.
C = $2\mathrm{\pi r}$
⇒ r = $\frac{\mathrm{C}}{2\mathrm{\pi }}$ cm
⇒ r = $\left(\frac{57.2}{2}\times \frac{7}{22}\right)$ cm = 9.1 cm
Thus, radius of the given circle is 9.1 cm.