ГДЗ по геометрии 9 класс Атанасян Задание 1109

\[\boxed{\mathbf{1109.ОК\ ГДЗ - домашка\ на}\ 5}\]

\[Дано:\]

\[R = 6\ см\ \ и\ \ \text{α.}\]

\[Найти:\]

\[l - ?.\]

\[Решение.\]

\[l = \frac{\text{πR}}{180{^\circ}} \bullet \alpha.\]

\[\textbf{а)}\ \alpha = 30{^\circ}:\]

\[l = \frac{6\pi}{180{^\circ}} \bullet 30{^\circ} = \frac{6\pi}{6} = \pi\ см;\]

\[\textbf{б)}\ \alpha = 45{^\circ}:\]

\[l = \frac{6\pi}{180{^\circ}} \bullet 45{^\circ} = \frac{6\pi}{4} = \frac{3}{2}\text{π\ }см;\]

\[\textbf{в)}\ \alpha = 60{^\circ}:\]

\[l = \frac{6\pi}{180{^\circ}} \bullet 60{^\circ} = \frac{6\pi}{3} = 2\pi\ см;\]

\[\textbf{г)}\ \alpha = 90{^\circ}:\]

\[l = \frac{6\pi}{180{^\circ}} \bullet 90{^\circ} = \frac{6\pi}{2} = 3\pi\ см.\]