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 congruent.

Front

What can be concluded if ∠9 ≅ ∠12?

Back

If ∠9 ≅ ∠12, then none of the lines can be determined to be parallel.

Front

What is the Transitive Property in geometry?

Back

The Transitive Property states that if A = B and B = C, then A = C.

Front

What does it mean if two angles are congruent?

Back

If two angles are congruent, it means they have the same measure.

Front

What is the relationship between corresponding angles when two lines are parallel?

Back

When two lines are parallel, corresponding angles are congruent.

Front

What is the definition of parallel lines?

Back

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

Front

What is the Alternate Interior Angles Theorem?

Back

The Alternate Interior Angles Theorem states that if two parallel lines are cut by a transversal, then each pair of alternate interior angles is congruent.

Front

What is the Consecutive Interior Angles Theorem?

Back

The Consecutive Interior Angles Theorem states that if two parallel lines are cut by a transversal, then each pair of consecutive interior angles is supplementary.

Front

What is a transversal in geometry?

Back

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

Front

How can you prove that two lines are parallel using angle relationships?

Back

You can prove that two lines are parallel by showing that corresponding angles are congruent or that alternate interior angles are congruent.