1. The problem asks to identify the angle relationship between two angles labeled "1" and "2" formed by two intersecting lines. 2. When two straight lines intersect, they form four angles. The pairs of angles opposite each other are called vertically opposite angles. 3. Vertically opposite angles are always equal. 4. Adjacent angles formed by intersecting lines are supplementary, meaning their measures add up to 180 degrees. 5. Since angles "1" and "2" are adjacent angles (next to each other), their relationship is that they are supplementary. 6. This means: $$\text{angle } 1 + \text{angle } 2 = 180^\circ$$ 7. Therefore, the angle relationship between angles "1" and "2" is that they are supplementary angles.