b.) alternate angles are equal
If a transversal intersects two parallel lines, each pair of alternate angles are equal.
Given: Two parallel lines and a transversal.
Prove: Each pair of alternate angles are equal (same degrees).
Alternate interior angles are formed when a transversal passes through two lines. The angles that are formed on opposite sides of the transversal and inside the two lines are alternate interior angles. The theorem says that when the lines are parallel, that the alternate interior angles are equal
Try using a protractor to measure the angles to prove that they have the same angle degrees.