Definition
Reflex angle
A reflex angle is greater than 180° but less than 360°.
What it means
Imagine turning past a straight line but stopping before a full turn. That wide sweep is the reflex angle. The smaller angle between the same rays and the reflex angle together make 360°.
Remember it
More than a half-turn, less than a full turn.
Example
The smaller angle between two rays is 110°. Angles all the way around a point total 360°, so the reflex angle is 360° − 110° = 250°. Because 250° lies between 180° and 360°, it is reflex.
Watch for
An angle of 180° is straight, and an angle of 360° is a full turn; neither is reflex.
Common mix-up
A drawing often highlights the smaller angle. Follow the marked sweep or the stated measure to know which angle is meant.
Exact meaning
A reflex angle measures more than 180° and less than 360°. For the same two rays, it is the larger turn around their shared vertex.