Geometry · Points, Lines & Angles
Linear Pair
HSG-CO.A.1
Definition
Two adjacent angles that form a straight line, so their measures sum to 180 degrees.
Examples
- A linear pair of 130 and 50 degrees sums to 180 degrees.
- Any two adjacent angles whose non-shared sides form a straight line are a linear pair.
Key rule
A linear pair is always supplementary — the angles sum to 180 degrees.
Memory hook
Adjacent angles that make a straight line.