Parallel Lines and a Transversal

Front

What are parallel lines?

Back

Parallel lines are lines in a plane that never meet; they are always the same distance apart.

Front

What is a transversal?

Back

A transversal is a line that intersects two or more lines at different points.

Front

What are corresponding angles?

Back

Corresponding angles are pairs of angles that are in the same position on different parallel lines cut by a transversal.

Front

What are alternate interior angles?

Back

Alternate interior angles are pairs of angles that lie between the two lines and on opposite sides of the transversal.

Front

What are same-side interior angles?

Back

Same-side interior angles are pairs of angles that lie between the two lines and on the same side of the transversal.

Front

What does it mean for angles to be supplementary?

Back

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

Front

How can you prove that two lines are parallel using angles?

Back

If a transversal creates corresponding angles that are equal, or alternate interior angles that are equal, then the lines are parallel.

Front

What is the relationship between the angles formed when a transversal crosses parallel lines?

Back

When a transversal crosses parallel lines, corresponding angles are equal, alternate interior angles are equal, and same-side interior angles are supplementary.

Front

What is the sum of the interior angles of a triangle?

Back

The sum of the interior angles of a triangle is always 180 degrees.

Front

What is the exterior angle theorem?

Back

The exterior angle theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two opposite interior angles.