Key Angle Relationships
When lines intersect, they create special angle relationships that follow predictable patterns. Vertical angles are angles that appear across from each other when two lines intersect. They're always congruent (equal in measure), which is super helpful in solving geometry problems.
Adjacent angles sit next to each other and share a common side. Think of them as neighbors that share a wall! When adjacent angles form a straight line (180°), they create what's called a linear pair. Linear pairs are always supplementary.
💡 Remember this shortcut: Vertical angles are always equal, and angles in a linear pair always add up to 180°!
Complementary angles add up to 90° (a right angle). For example, 30° and 60° are complementary because 30° + 60° = 90°. Supplementary angles add up to 180° (a straight line). For instance, 30° and 150° are supplementary because 30° + 150° = 180°.