Geometry · Points, Lines & Angles

Adjacent Angles

HSG-CO.A.1

Definition

Two angles that share a common vertex and side but have no interior points in common.

Examples

  • Angle 1 and angle 2 share a vertex and a side without overlapping.
  • Two angles that together form a straight line are adjacent angles.

Key rule

Adjacent angles share a vertex and a side but never overlap.

Memory hook

Next-door angles — sharing a side, not overlapping.