Parallel Line Proofs

Front

What is the definition of Parallel Lines?

Back

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

Front

What are Corresponding Angles?

Back

Corresponding angles are pairs of angles that are in similar positions at each intersection where a straight line crosses two others.

Front

What is the Alternate Interior Angles Theorem?

Back

If two parallel lines are cut by a transversal, then each pair of alternate interior angles is congruent.

Front

What is the definition of Transitive Property?

Back

If a = b and b = c, then a = c. This property is often used in proofs involving congruence.

Front

What are Alternate Exterior Angles?

Back

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

Front

What is the definition of Congruent Angles?

Back

Congruent angles are angles that have the same measure.

Front

What is the Same-Side Interior Angles Postulate?

Back

If two parallel lines are cut by a transversal, then each pair of same-side interior angles is supplementary.

Front

What is the definition of a Transversal?

Back

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

Front

What is the definition of Vertical Angles?

Back

Vertical angles are the angles opposite each other when two lines cross. They are always congruent.

Front

What is the Substitution Property?

Back

If a = b, then b can be substituted for a in any expression.