Reflex angle

Definition: An angle whose measure is greater than 180° and less than 360°
Try this Adjust the angle below by dragging an orange dot and see how the angle ABC behaves. Note that it is a reflex angle only when it is between 180° and a full circle.

Some might argue than reflex angles are not real. They are the 'other half' of a smaller angle. Indeed if you refer to the angle ABC without qualifying it,it is generally assumed that you mean the smallest angle. If you mean the large part of the angle, you must specify it by saying 'reflex angle ABC'.

Types of angle

Altogether, there are six types of angle as listed below. Click on an image for a full description of that type and a corresponding interactive applet.

Acute angle Right Angle Obtuse Angle
Acute angle
Less than 90°
Right angle
Exactly 90°
Obtuse angle
Between 90° and 180°
Straight Angle Reflex Angle Full Angle
Straight angle
Exactly 180°
Reflex angle
Between 180° and 360°
Full angle
Exactly 360°

Other angle topics


Angle Types

Angle relationships