Complementary angles – two angles whose sum is 90° (e.g., 30° and 60°).Supplementary angles – two angles whose sum is 180° (e.g., 110° and 70°).Vertical angles – opposite angles formed by two intersecting lines (e.g., both are 45°).Adjacent angles – two angles that share a common side and vertex (e.g., 40° and 50°).