Vocabulary

Vertex - is the point where two rays of an angle meet.

Vertical Angles - Two angles are vertical if they are opposite angles formed by the intersection of two lines.

Adjacent Angles - Two angles are adjacent if they share a common vertex, a common side, and do not overlap.

Straight Angle - exactly 180°

Complementary Angles - two angles whose sum of measures is 90°.

Supplementary Angles - two angles whose sum of measures is 180°.

Concepts

Classify angles as a vertical, complementary, or supplementary angles.

Rules

Use the properties of angles given above to determine if the angles are vertical, supplementary, or complementary angles.

Example

Identify each pair of angles as vertical, supplementary, or complementary angles.

Solution

Add the two angles together.

135° + 45° = 180°

Supplementary angles are two angles whose sum is 180 degrees.

Answer: Supplementary angles

Pre-requisite Skills

Measure Angles (6.10.1)

Classify Angles (6.10.2)

Angle Relationships (6.10.5)