Question

Find the circumference of the circles with the following radius: (Take $\pi$ = $\frac{22}{7}$ )

1. 14 cm
2. 28 mm
3. 21 cm

Answer 1

(a) $r = 14 \;cm$
Circumference = $2\pi r$

= $2\times \frac{22}{7}\times 14$

= $88\;cm$

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(b) $r=28 \; mm$
Circumference = $2\pi r$

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

= $176\;mm$

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(c) $r = 21 \; cm$
Circumference = $2\pi r$

$2\times \frac{22}{7}\times 21$

= $132\;cm$