Решебник по геометрии 9 класс Мерзляк Задание 182

\[1)\ a = 90{^\circ}:\]

\[S_{n} = (n - 2) \bullet 180{^\circ} = n \bullet 90{^\circ}\]

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

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

\[n = 4\ стороны.\]

\[Ответ:\ \ 4.\]

\[2)\ a = 108{^\circ}:\]

\[S_{n} = (n - 2) \bullet 180{^\circ} = n \bullet 108{^\circ}\]

\[n - 2 = \frac{3}{5}\text{n\ \ }\]

\[\frac{2}{5}n = 2\ \ \]

\[n = 5\ сторон.\]

\[Ответ:\ \ 5.\]