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

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Other angle topics

General

• Angle definition
• Degrees
• Radians
• Angle bisector
• Subtended angle
• Interior of an angle
• Included angle

Angle Types

• Acute angle
• Right angle
• Obtuse angles
• Straight angle
• Reflex angle
• Full angle

Angle relationships

• Vertical angles
• Complementary angles
• Supplementary angles
• Linear pair
• Adjacent angles
• Corresponding angles
• Alternate interior angles
• Alternate exterior angles
• Interior angles of a transversal
• Exterior angles of a transversal