\[\boxed{\mathbf{58.}\mathbf{ОК\ ГДЗ - домашка\ на}\ 5}\]
\[Рисунок\ по\ условию\ задачи:\]
\[Дано:\]
\[\textbf{а)}\ \angle ABC = 111{^\circ}\]
\[\textbf{б)}\ \angle ABC = 90{^\circ}\]
\[\textbf{в)}\ \angle ABC = 15{^\circ}\]
\[Найти:\]
\[\angle CBD - ?\]
\[Решение.\]
\[Сумма\ смежных\ углов\ \]
\[равна\ 180{^\circ},\ следовательно:\]
\[\angle ABC + \angle CBD = 180{^\circ}\]
\[\angle CBD = 180{^\circ} - \angle\text{ABC}\]
\[\textbf{а)}\ \angle CBD = 180{^\circ} - 111{^\circ} = 69{^\circ}.\]
\[\textbf{б)}\ \angle CBD = 180{^\circ} - 90{^\circ} = 90{^\circ}.\]
\[\textbf{в)}\ \angle CBD = 180{^\circ} - 15{^\circ} = 165{^\circ}.\]
\[Ответ:а)\ 69{^\circ};\]
\[\ \ \ \ \ \ \ \ \ \ \ \ \ \ б)\ 90{^\circ};\]
\[\ \ \ \ \ \ \ \ \ \ \ \ \ \ в)\ 165{^\circ}.\]