1. **State the problem:** We are given two intersecting lines forming angles numbered 1 through 8. Angle 1 measures 111° and we need to find the measure of angle 7. 2. **Identify relationships:** When two lines intersect, opposite (vertical) angles are equal. Also, adjacent angles on a straight line sum to 180°. 3. **Find angle 2:** Since angle 1 and angle 2 are adjacent on a straight line, their measures add up to 180°. $$\text{angle 1} + \text{angle 2} = 180^\circ$$ $$111^\circ + \text{angle 2} = 180^\circ$$ $$\text{angle 2} = 180^\circ - 111^\circ = 69^\circ$$ 4. **Find angle 7:** Angle 2 and angle 7 are vertical angles (opposite angles formed by intersecting lines), so they are equal. $$\text{angle 7} = \text{angle 2} = 69^\circ$$ **Final answer:** $$\boxed{69^\circ}$$