Question

Find the circumference of a circle whose radius is
(i) $28cm$
(ii) $10.5cm$
(iii) $3.5m$

Answer 1

(i) Radius, $r=28cm$
$\therefore$ Circumference of the circle, $C=2\pi r$

$=(2\times \frac{22}{7}\times 28)$

$=176cm$

Hence, the circumference of the given circle is $176cm.$
(ii) Radius, $r=10.5cm$
$\therefore$ Circumference of the circle, $C=2\pi r$

$=(2\times \frac{22}{7}\times 10.5)=66cm$

Hence, the circumference of the given circle is $66cm.$
(iii) Radius, $r=3.5m$
$\therefore$ Circumference of the circle, $C=2\pi r$

$=(2\times \frac{22}{7}\times 3.5)=22m$

Hence, the circumference of the given circle is $22m.$