How Are The Alternate Interior Angles Theorem And The Alternate Exterior Angles Theorem Different. The Alternate Exterior Angles Theorem states that when two parallel lines are cut by a transversal the resulting alternate exterior angles are congruent. 1 7 and 4 6.
So in the figure below if k l then. Alternate exterior angles are created in the space outside the parallel lines on alternating sides. Hence they are equal.
Let L1 and L2 be parallel lines cut by a transversal T such that 1 and 3 are alternate interior angles.
At each intersection the corresponding angles lie at the same place. By the alternate interior angles theorem x and 20 are the alternate interior angles. Alternate interior angles are angles formed when two parallel or non-parallel lines are intersected by a transversal. Because these lines are parallel the theorem tells us that the alternate interior angles are congruent.