\[Рисунок\ в\ учебнике.\]
\[\angle AOB = \angle DOC.\]
\[1)\ \angle AOC = \angle AOB + \angle BOC\]
\[\angle AOB = \angle AOC - \angle BOC.\]
\[2)\ \angle BOD = \angle BOC + \angle DOC\]
\[\angle DOC = \angle BOD - \angle BOC.\]
\[3)\ Из\ равенства\ углов:\]
\[\angle AOB = \angle DOC;\]
\[\angle AOC = \angle BOD.\]
\[Ответ:\ \ да.\]