These are the ANGLE BISECTORS of a triangle.[br]Their point of concurrency is the INCENTER.

Notice that the INCENTER is equidistant to the SIDES of the triangle.[br]Drag the vertices of the triangle around, and notice that the INCENTER is ALWAYS equidistant to the SIDES of the triangle.[br][br]An interesting thing happens when the triangle is equilateral. See if you can find out what it is!