Answer:
[tex]\Delta s = \frac{71\pi}{60}\cdot r[/tex]
Step-by-step explanation:
Let r be the radius of the circle, the measure of the arc is equal to:
[tex]\Delta s = \frac{213^{\circ}}{360^{\circ}}\cdot 2\pi \cdot r[/tex]
[tex]\Delta s = \frac{71\pi}{60}\cdot r[/tex]