Lines and Angles

Front

What is a line?

Back

A straight path that extends infinitely in both directions.

Front

What is a ray?

Back

A part of a line that has a fixed starting point and extends infinitely in one direction.

Front

What is a line segment?

Back

A part of a line that has two endpoints.

Front

What is an angle?

Back

The figure formed by two rays with a common endpoint called the vertex.

Front

What is a right angle?

Back

An angle that measures exactly 90 degrees.

Front

What is an acute angle?

Back

An angle that measures less than 90 degrees.

Front

What is an obtuse angle?

Back

An angle that measures more than 90 degrees but less than 180 degrees.

Front

What is a straight angle?

Back

An angle that measures exactly 180 degrees.

Front

What are complementary angles?

Back

Two angles that add up to 90 degrees.

Front

What are supplementary angles?

Back

Two angles that add up to 180 degrees.