The rule is that an arc has the same degree measure as does the central angle that cuts it off. Arc CE is cut off by angle made by C-the center of the circle-E. That angle measures 85 degrees, so arc CE measures 85 degrees. Make sure you are not confusing arc measure with arc length, which is very much NOT THE SAME!!
The same goes for arc DE. It is cut off by a central angle measuring 145, so arc DE measures 145 degrees. All the way around a circle, regardless of how big the circle is, is 360 degrees. Therefore, arc DC = 360 - 85 - 145 and
