If you want to determine if a point is on the perpendicular bisector of a line segment, the Perpendicular Bisector Theorem and its converse might come in handy. This tutorial gives a great example of how to tell if a given point is a perpendicular bisector of a segment!
When solving for length or angle measures in triangles, theorems you have learned previously can come in handy! Watch this tutorial to find out how to use the Perpendicular Bisector Theorem to find out the side lengths of a triangle.