Geometry Lines and Angles

Front

What is a line of symmetry?

Back

A line that divides a shape into two identical parts that are mirror images of each other.

Front

What is a ray?

Back

A part of a line that starts at a 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

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

Front

What is a protractor used for?

Back

A tool used to measure angles in degrees.

Front

What is the measure of a right angle?

Back

90 degrees.

Front

What is the measure of a straight angle?

Back

180 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 vertical angle?

Back

Angles that are opposite each other when two lines intersect; they are equal.