The angle bisectors of a triangle ABC meet in a single point called the incenter. The incenter M is equidistant from the three sides of the triangle. The incenter is the center of the incircle, the largest circle inside ABC. The incircle is tangent to all three sides.
You can change the locations of E, H, and K on the angle bisectors.
If DE and EF are the perpendiculars from E to AC and AB, then |DE| = |EF|. Similarly, |GH| = |HI| and |JK| = |KL|.