Question

Find the circumference of a circle whose radius is
(i) 14 cm
(ii) 10 m
(iii) 4 km

Answer 1

(i) The circumference C of a circle of radius 'r' is given by:
C = 2$\mathrm{\pi }$r
Here, r = 14 cm
∴ C = $2\times \frac{22}{7}\times 14=88\mathrm{cm}$.
(ii) The circumference C of a circle of radius 'r' is given by:
C = 2$\mathrm{\pi }$r
Here, r = 10 m
∴ C = $2\times \frac{22}{7}\times 10=62.86\mathrm{m}$.
(iii) ​The circumference C of a circle of radius 'r' is given by:
C = 2$\mathrm{\pi }$r
Here, r = 4 km
∴ C = $2\times \frac{22}{7}\times 4=25.142\mathrm{km}$.