What is the length of the arc whose central angle is 30° and radius of the circle is 21 cm?

$heta=30^{circ}=frac{30 imes pi}{180}=frac{pi}{6}$ radian

$herefore heta=frac{l}{r}$

$Rightarrow frac{pi}{6}=frac{l}{21}$

$Rightarrow l=frac{21 pi}{6}=frac{21}{6} imes frac{22}{7}=11 mathrm{~cm} .$