The document discusses bisectors of triangles, including perpendicular bisectors and angle bisectors. It defines key terms like perpendicular bisector, concurrent lines, circumcenter, and incenter. Theorems are presented about the properties of points on perpendicular bisectors, including that they are equidistant from the endpoints of the bisected segment. Similarly, points on angle bisectors are equidistant from the sides of the bisected angle. The circumcenter and incenter are shown to be equidistant from the vertices and sides of a triangle respectively. Examples demonstrate applying the concepts.