Parallel Lines Cut by a Transversal

Transversal

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

Corresponding Angles

Angles that lie on the same side of the transversal and in the same "position."

Alternate Interior Angles

Angles that lie on opposite sides of the transversal and in between the two lines.

Alternate Exterior Angles

Angles that lie on opposite sides of the transversal and outside the two lines.

Consecutive Interior Angles

Angles that lie on the same side of the transversal and in between the two lines.

Vertical Angles

Angles that are across from each other at two intersecting lines.

Corresponding Angles Theorem

If two parallel lines are cut by a transversal, then the pairs of corresponding angles are congruent

Alternate Interior Angles Theorem

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

Alternate Exterior Angles Theorem

If two parallel lines are cut by a transversal, then the pairs of alternate exterior angles are congruent

Consecutive Interior Angles Theorem

If two parallel lines are cut by a transversal, then the pairs of consecutive interior angles are supplementary.

Vertical Angles Theorem

If two angles are vertical angles, then they are congruent.

Corresponding Angles Converse

If two lines are cut by a transversal so the corresponding angles are congruent, then the lines are parallel.

Alternate Interior Angles Converse Theorem

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

Alternate Exterior Angles Converse Theorem

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

Consecutive Interior Angles Converse Theorem

If two lines are cut by a transversal so that consecutive interior angles are supplementary, then the lines are parallel