Proving Parallel Lines

Front

What are parallel lines?

Back

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

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 are alternate interior angles?

Back

Alternate interior angles are pairs of angles that lie between two lines and on opposite sides of a transversal. If the lines are parallel, these angles are congruent.

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 Consecutive Interior Angles Theorem?

Back

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

Front

How can you prove that two lines are parallel using angles?

Back

You can prove that two lines are parallel if you can show that a pair of corresponding angles are congruent, alternate interior angles are congruent, or consecutive interior angles are supplementary.

Front

What is the value of x if angle 1 is 50 degrees and angle 3 is 130 degrees?

Back

x = 130 degrees, since angle 1 and angle 3 are corresponding angles.

Front

If angle 5 is 70 degrees, what is the measure of angle 6 if lines are parallel?

Back

Angle 6 is also 70 degrees, as corresponding angles are congruent.

Front

What is the relationship between angle 2 and angle 4 if lines are parallel?

Back

Angle 2 and angle 4 are alternate interior angles and are congruent.

Front

If angle 1 is 40 degrees, what is the measure of angle 8 if lines are parallel?

Back

Angle 8 is 140 degrees, as it is a corresponding angle.