Angles

An angle is formed by two rays (the sides of the angle) sharing a common endpoint (the vertex). Angles are measured in degrees or radians. Angle chasing is a technique for finding unknown angles using known angle relationships in geometric figures.

Important properties

• Sum of angles on a straight line is 180°.

• Sum of angles around a point is 360°.

• Angles in a triangle add up to 180°.

• Vertically opposite angles are equal.

• Alternate and corresponding angles (when lines are parallel) have special properties.