Question

Explain? /:
Use a paragraph proof to prove the alternate interior angles theorem.

Given: Line AB is parallel to line CD

Prove: Alternate interior angles are congruent

Answer 1

@dpaInc @SmoothMath

Answer 2

Given that two parallel lines are cut by a transversal then and 1 is congruent to angle 5 by the corresponding angle theorem. Angle 1 is congruent to angle 3 by the vertical angle theorem. Since angle 5 = angle 1 and angle 1 = angle 3, then angle 5 is congruent to angle 3 by the transitive property and therefore alternate interior angles are congruent.