What is a 90 degree angle?

A 90 degree angle, also known as a right angle, is an angle that measures exactly 90 degrees.

  • It is a quarter of a full rotation (360 degrees).

  • Right angles are fundamental in geometry and trigonometry.

  • A perpendicular relationship between two lines or planes indicates that they intersect at a right angle.

  • Right angles are often indicated by a small square drawn in the corner where the lines meet.

  • The sides forming a right angle are called legs or cathetus.