1. Найти \(\angle a_1\), \(\angle b_1\) 2. \(\angle 1 + \angle 3 = 70^\circ\). Найти \(\angle 2, \angle 4\) 3. \(\angle m_1n_1 + \angle m_1n + \angle n_1n = 240^\circ\). Найти \(\angle m_1n\) 4. \(\angle 1 - \angle 2 = 120^\circ\). Найти \(\angle 3, \angle 4\) 5. \(\angle 1 + \angle 3 = 7/4 \cdot \angle 4\). Найти \(\angle 1, \angle 2, \angle 3, \angle 4\) 6. \(\angle 1 + \angle 2 + \angle 3 = 5 \cdot \angle 4\). Найти \(\angle 4\) 7. \(\angle 1 = \angle 2 + \angle 3\). Найти \(\angle 1, \angle 2, \angle 3\) 8. AB \(\perp\) CD. Найти \(\angle AOE\)