Решебник по геометрии 9 класс Мерзляк Задание 181

\[1)\ a = 60{^\circ}:\]

\[S_{n} = (n - 2) \bullet 180{^\circ} = n \bullet 60{^\circ}\]

\[n - 2 = \frac{1}{3}\text{n\ \ \ }\]

\[\frac{2}{3}n = 2\ \ \ \]

\[n = 3\ стороны.\]

\[Ответ:\ \ 3.\]

\[2)\ a = 171{^\circ}:\]

\[S_{n} = (n - 2) \bullet 180{^\circ} = n \bullet 171{^\circ}\]

\[n - 2 = \frac{19}{20}\text{n\ \ \ }\]

\[\frac{1}{20}n = 2\ \ \]

\[n = 40\ сторон.\]

\[Ответ:\ \ 40.\]