Question

Find the circumference of a circle whose radius is
(i) $28\text{cm}$
(ii) $10.5\text{cm}$

Answer 1

Circumference of a circle of radius $r$ is $2\pi r$

(i) $r=28\text{cm}$

$⟹$ Circumference $=2\times \frac{22}{7}\times 28=176{\text{cm}}^2$

(ii) $r=10.5\text{cm}$

$⟹$ Circumference $=2\times \frac{22}{7}\times 10.5=66{\text{cm}}^2$