Angle Relationships

Corresponding angles are pairs of angles that are in the same position on different parallel lines cut by a transversal. They are equal in measure.

Alternate interior angles are pairs of angles that lie between two parallel lines and on opposite sides of a transversal. They are equal in measure.

Vertical angles are the angles opposite each other when two lines intersect. They are always equal in measure.

Supplementary angles are two angles whose measures add up to 180 degrees.

Complementary angles are two angles whose measures add up to 90 degrees.

The alternate interior angle to angle 3 is angle 5.

Corresponding angles are equal when two parallel lines are cut by a transversal.

Angle 2 and angle 6 are equal in measure.

The sum of the measures of supplementary angles is 180 degrees.

The sum of the measures of complementary angles is 90 degrees.