Pairs of angles

• The amount of rotation is called the measure of the angle. Degree (°) is the unit of measuring angles.

• 1 rotation = 360°, 1° = 60′, 1’= 60”

• If two angles in the same plane have a common vertex and a common side; but have interiors with no points in common, the angles are adjacent.

• The sum of linear pairs of angles is always 180°

• The sum of the adjacent angles on one side of a line is 180°

• If two lines intersect then the vertically opposite angles are equal.

• If the sum of two angles is 180°, then angles are called supplementary angles, and if their sum is 90°, they are called complementary angles.