1. Для \(18^\circ\): \(\frac{18 \times \pi}{180} = \frac{\pi}{10}\) радиан.
2. Для \(108^\circ\): \(\frac{108 \times \pi}{180} = \frac{3\pi}{5}\) радиан.
3. Для \(-30^\circ\): \(\frac{-30 \times \pi}{180} = -\frac{\pi}{6}\) радиан.
Ответ: \(\frac{\pi}{10}\), \(\frac{3\pi}{5}\), \(-\frac{\pi}{6}\)