Find, in terms of π, the length of the arc that subtends an angle

The arc length l of a sector of an angle θ in a circle of radius r is given by

$l=\frac{\theta}{360^{\circ}} \times 2 \pi r$

It is given that $r=4 \mathrm{~cm}$ and $\theta=30^{\circ}$. Substituting the value of $r$ and $\theta$ in above equation,

$l=\frac{30^{\circ}}{360^{\circ}} \times 2 \pi \times 4 \mathrm{~cm}$

$=\frac{2 \pi}{3} \mathrm{~cm}$