Geometry · Points, Lines & Angles
Straight Angle
HSG-CO.A.1
Definition
An angle that measures exactly 180 degrees, forming a straight line.
Examples
- Points A, B, and C on a straight line form a 180 degree straight angle.
- A linear pair of angles always adds up to a straight angle, 180 degrees.
Key rule
A straight angle looks like a straight line, not a bent corner.
Memory hook
A flat angle — exactly 180 degrees.