First, students will learn what the perpendicular bisector theorem is, and why it's true. Then students will learn what the converse of the perpendicular bisector theorem is, and why it's true. Before attempting to understand these proofs, students must know the definition of perpendicular bisector, the isosceles triangle theorem, and the SAS congruence theorem. Watch the first part of this video for a proof of the perpendicular bisector theorem and its converse.