Parallel Line Proofs

Front

What is the Vertical Angles Theorem?

Back

The Vertical Angles Theorem states that when two lines intersect, the opposite (or vertical) angles are equal.

Front

What must be proven in a parallel line proof?

Back

In a parallel line proof, you must prove that two lines are parallel based on the relationships of the angles formed by a transversal.

Front

What are Alternate Interior Angles?

Back

Alternate Interior Angles are pairs of angles that are on opposite sides of a transversal and inside the two lines. If the lines are parallel, these angles are equal.

Front

What are Corresponding Angles?

Back

Corresponding Angles are pairs of angles that are in the same position on two different parallel lines cut by a transversal. If the lines are parallel, these angles are equal.

Front

What is the Corresponding Angles Postulate?

Back

The Corresponding Angles Postulate states that if two parallel lines are cut by a transversal, then each pair of corresponding angles is equal.

Front

What is a transversal in geometry?

Back

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

Front

How do you determine if two lines are parallel using angle relationships?

Back

If the alternate interior angles are equal or the corresponding angles are equal, then the two lines are parallel.

Front

What is the definition of supplementary angles?

Back

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

Front

What is the definition of complementary angles?

Back

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

Front

What is the relationship between same-side interior angles when two lines are parallel?

Back

When two lines are parallel, same-side interior angles are supplementary, meaning they add up to 180 degrees.