In a circle, or congruent circles, congruent central angles have congruent arcs.
therefore, we can conclude:
[tex]\angle AOB\cong\angle COD[/tex]
By definition, all radii of a circle are congruent, since all the points on a circle are the same distance from the center, so:
[tex]AO\cong BO\cong CO\cong DO[/tex]
