Question

what is the circumference of a circle whose radius is 21cm

Answer 1

circumference =2×pie ×r
circumference =2×22/7×21
circumference =132cm

Answer 2

Radius = 21cm

Circumference= 2πr

or, 2×22/7×21

or,
$2 \times \frac{22}{7} \times 21$
= 132 cm


hope this helps you mate ❤