Proving Lines Parallel Lesson 2 - 5 Proving Lines Parallel

Proving Lines Parallel Postulates and theorems If two lines are cut by a transversal and corresponding angles are congruent, then the lines are parallel.

Proving Lines Parallel Postulates and theorems If two lines are cut by a transversal and alternate interior angles are congruent, then the lines are parallel.

Proving Lines Parallel Postulates and theorems If two lines are cut by a transversal and consecutive interior angles are supplementary, then the lines are parallel.

Proving Lines Parallel Postulates and theorems If two lines are cut by a transversal and consecutive exterior angles are supplementary, then the lines are parallel.

Proving Lines Parallel Examples Find the value of x which will make lines a and lines b parallel. 1. 2. 4. 3. ANSWERS: 20 deg; 50 deg; 45 deg; 20 deg

Ways to Prove Two Lines Parallel Show that corresponding angles are equal. Show that alternative interior angles are equal. Show that consecutive interior angles are supplementary. Show that consecutive exterior angles are supplementary. In a plane, show that the lines are perpendicular to the same line.