Parallel Lines Proofs

Front

What are vertical angles?

Back

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

Front

What is the Corresponding Angles Postulate?

Back

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

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 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 Angle Addition Postulate?

Back

If point B is in the interior of angle AOC, then the measure of angle AOB plus the measure of angle BOC equals the measure of angle AOC.

Front

What does it mean for angles to be congruent?

Back

Angles are congruent if they have the same measure.

Front

What is the Transitive Property of Equality?

Back

If a = b and b = c, then a = c.

Front

What is the Substitution Property?

Back

If two values are equal, one can be substituted for the other in any expression.

Front

What is the definition of adjacent angles?

Back

Adjacent angles are two angles that share a common side and a common vertex but do not overlap.