Congruence in Right Triangles
Theorem. Perpendicular Bisector Theorem
In a given plane, a point is on the perpendicular bisector of a segment if and only if it is equidistant from the endpoints of the segment.
Restatement
In a given plane, a point P is on the perpendicular bisector of
if and only if
Since the statement is biconditional, you need to prove two implications:
If point P is on the perpendicular bisector of then
If then point P is on the perpendicular bisector of
