[tex]arc \ length= \pi r ( \frac{C}{180} ) \ \ \ \ [C= central \ angle, \ r=radius, \pi =3.14] \\ \\ arcAC=3.14*7 *\frac{45}{180} =21.98*0.25 \approx 5.5 \ units[/tex]
If you need to find the arc measurement in degrees, then:
degree measure of a minor arc is the same as the measure of its corresponding central angle, so
arc AC = ∠ABC = 45°