Now write your conclusion in part D as a theorem, and prove the theorem using a two-column proof. When you write the proof, refer to the diagram you created in part A. As part of the proof, you will have to construct a line through point A parallel to . Mark the point where the new line intersects the angle bisector, , and label the point E. Take a screenshot of the construction, save it, and insert the image in the space below before you begin your written proof.