Question

the lenght of arc AB whose angle is 60 degrees and radius is 21cm find arc of the sector

Answer 1

Radius, r = 21 cm
$angle \: \: \theta = 60 \: degrees \\ = 60 \times \frac{\pi}{180} = \frac{\pi}{ 3} \: radian$
$arc \: \: length = r \times \theta \\ = 21 \times \frac{\pi}{3} = 7\pi = 7 \times \frac{22}{7} = 22\: cm$