In circle with centre O. AC and BD are two chords. AC and BD meet at E when produced. If AB is the diameter and  $$\angle$$ AEB=$$68^\circ$$, then the measure of $$\angle$$ DOC is

In $$\triangle$$ AEB,
$$\angle EAB + \angle EBA + 68 = 180$$
$$\angle EAB + \angle EBA = 112$$
$$\angle EAB = \angle OCA$$
$$\angle EBA = \angle ODB$$
In quadrilateral EDOC,
68 + $$\angle OCE + \angle DOC + \angle ODE = 360$$
68 + 180 - $$\angle OCA + 180 - \angle ODB + \angle DOC = 360$$
68 + 180 - $$\angle EAB + 180 -\angle EBA + \angle DOC = 360$$
68 + 180 - 112 + $$\angle DOC = 360$$
$$\angle DOC = 44\degree$$