Answer:
120 degrees
Explanation:
we know that the measure of the arc length of the arc in degrees is 30 degrees we also know that the measure of the angle inside of it is half its size.
Therefore, angle DOA is 60 and it is supplementary to DOC.
180 - 60 = DOC = 120 degrees.
Great question, had to think about and look up some laws.
Hope this helps.