Решебник по геометрии 7 класс Мерзляк Задание 60

\[Луч\ BD\ лежит\ внутри\ \angle\text{ABC.}\]

\[1)\ \angle ABD = 54{^\circ};\ \angle CBD = 72{^\circ}:\]

\[\angle ABC = \angle ABD + \angle CBD =\]

\[= 54{^\circ} + 72{^\circ} = 126{^\circ}.\]

\[Ответ:\ \ 126{^\circ}.\]

\[2)\ \angle ABC = 158{^\circ};\ \angle ABD = 93{^\circ}:\]

\[\angle ABC = \angle ABD + \angle CBD\]

\[\angle CBD = \angle ABC - \angle ABD =\]

\[= 158{^\circ} - 93{^\circ} = 65{^\circ};\]

\[Ответ:\ \ 65{^\circ}.\]