Chord AB of a circle subtends an angle of 120° at the centre O of t...

Question

Chord AB of a circle subtends an angle of 120° at the centre O of the circle. Find the length of arc AB, if radius of the circle is 21 cm.

Accepted Answer

$$	ext{Arc length}=\frac{	heta}{360}	imes2\pi r=\frac{120}{360}	imes2	imes\frac{22}{7}	imes21=\frac13	imes132=44\ cm$$