HOW DO YOU FIND THE ARC MEASURE IN A CIRCLE
I'm going to assume they gave you an arc length, and the radius of the circle.
\(\text{Let the arc length be }\ell \\ \\ \text{and let the radius be } r \\ \\ \text{then the arc measure or angle the arc subtends, }\theta \text{, is given by}\\ \\ \theta = 2 \pi \dfrac \ell r~radians = 360 \dfrac \ell r~degrees\)
This applies for
\(0 \leq \ell < r \\ \\ 0 \leq \theta < 2\pi ~radians\)