Transversal 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 Angle Theorem?

Back

If two parallel lines are cut by a transversal, then the resulting alternate interior angles are congruent.

Front

What are Alternate Exterior Angles?

Back

Alternate exterior angles are the angles that lie outside the two lines and on opposite sides of the transversal. They are congruent if the lines are parallel.

Front

What are Same Side Interior Angles?

Back

Same side interior angles are the angles that lie between the two lines and on the same side of the transversal. They are supplementary if the lines are parallel.

Front

What does it mean for angles to be supplementary?

Back

Two angles are supplementary if the sum of their measures is 180°.

Front

What is the Angle Addition Postulate?

Back

If point B lies in the interior of angle AOC, then m∠AOB + m∠BOC = m∠AOC.

Front

What is the definition of congruent angles?

Back

Congruent angles are angles that have the same measure.

Front

What is the definition of complementary angles?

Back

Two angles are complementary if the sum of their measures is 90°.

Front

What is the relationship between parallel lines and alternate interior angles?

Back

If two parallel lines are cut by a transversal, then the alternate interior angles are congruent.