Angle Relationships

Front

What is an angle?

Back

An angle is formed by two rays (sides of the angle) that share a common endpoint (the vertex).

Front

What is a right angle?

Back

A right angle is an angle that measures exactly 90 degrees.

Front

What is a straight angle?

Back

A straight angle is an angle that measures exactly 180 degrees.

Front

What is a reflex angle?

Back

A reflex angle is an angle that measures more than 180 degrees but less than 360 degrees.

Front

What are complementary angles?

Back

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

Front

What are supplementary angles?

Back

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

Front

What are vertical angles?

Back

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

Front

What are adjacent angles?

Back

Adjacent angles are two angles that share a common side and a common vertex but do not overlap.

Front

How do you find the measure of a missing angle in a triangle?

Back

The sum of the angles in a triangle is always 180 degrees. To find a missing angle, subtract the sum of the known angles from 180 degrees.

Front

How do you find the measure of a missing angle in a linear pair?

Back

In a linear pair, the two angles are supplementary. To find the missing angle, subtract the known angle from 180 degrees.