Classification of Angles



Classification of angles on the basis of their degree measures are given below:



Acute Angle:

An angle whose measure is more than 0° but less than 90° is called an acute angle. Angles having magnitudes 30°, 40°, 60° are all acute angles. In the adjoining figure, ∠X0Y represents an acute angle.

Acute Angle



∠X0Y < 90°


Right Angle:

An angle whose measure is equal to 90° is called a right angle. In the adjoining figure ∠ABC represents a right angle.

Right Angle



∠ABC = 90°


Obtuse Angle:

An angle whose measure is more than 90° but less than 180° is called an obtuse angle. In the adjoining figure, ∠XYZ represents an obtuse angle.

Obtuse Angle



∠XYZ > 90°

∠XYZ < 180°


Straight Angle:

An angle whose measure is equal to 180° is called a straight angle. In the adjoining figure, ∠XOY represents a straight angle.

Straight Angle



∠XOY = 180°


Reflex Angle:

An angle whose measure is more than 180° but less than 360° is called a reflex angle. In the adjoining figure, ∠POQ is a reflex angle. Angles having magnitudes 220°, 250°, 310° are all reflex angles.

Reflex Angle



∠POQ > 180°

∠POQ < 360°


Complete Angle:

An angle whose measure is equal to 360° is called a complete angle. In the adjoining figure, ∠BOA represents a complete angle.

60 minutes = 1 revolution = 1 complete angle.

Complete Angle



These are the adjoining figures of the classification of angles on the basis of their degree measures.



Lines and Angles

  • Fundamental Geometrical Concepts
  • Basic Geometrical Concepts
  • Angles
  • Classification of Angles
  • Related Angles
  • Some Geometric Terms and Results
  • Complementary Angles
  • Supplementary Angles
  • Complementary and Supplementary Angles
  • Adjacent Angles
  • Linear Pair of Angles
  • Vertically Opposite Angles
  • Parallel Lines
  • Transversal Line
  • Parallel and Transversal Lines

  • 7th Grade Math Problems

    8th Grade Math Practice

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