Key Concepts: Angle Relationships

Adjacent Angles

Adjacent angles are two angles that share a common vertex and a common side but have no interior points in common.

Vertical Angles

Vertical Angles are two non-adjacent angles formed by two intersecting lines. Vertical Angles are always congruent.

Complementary Angles

Two angles are complementary if the sum of their measures is 90°.

Supplementary Angles

Two angles are supplementary if the sum of their measures is 180°.

Linear Pair

A Linear Pair is a pair of adjacent angles whose non-common sides form a straight Line. Linear pairs are always supplementary (sum to 180°).

Perpendicular Lines

Two lines are perpendicular (⊥) if they intersect to form right angles (90°).