Understanding Angles and Their 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 linear pair of angles?

Back

A linear pair of angles are two adjacent angles that form a straight line, meaning their measures add up to 180°.

Front

What is a supplementary angle?

Back

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

Front

What is an acute angle?

Back

An acute angle is an angle that measures less than 90°.

Front

What is a right angle?

Back

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

Front

What is an obtuse angle?

Back

An obtuse angle is an angle that measures more than 90° but less than 180°.

Front

What is a straight angle?

Back

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

Front

What are complementary angles?

Back

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

Front

What is the vertex of an angle?

Back

The vertex of an angle is the point where the two rays meet.

Front

What are vertical angles?

Back

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