CONSTRUCTION OF THE INCENTER[br][br]1) Draw three points, A,B,C[br]2) Draw AB,BC,AC[br]3) Bisect any two angles and find the intersection, D[br]4) Draw perpendicular line to line segment AB through D, get E[br]5) Circle center D with radius E

Additional constructions needed:[br][br]1) How to construct an angle bisector, given an angle CAB[br] Assumption: AC and AB < O[br] Circle Center A with radius O, get points two points n, p[br] Circle Center n radius np[br] Circle Center p radius np, get two points q, r [br] Draw qr [br][br]2.) How to construct a perpendicular line to a line L through a point K[br] Assumption: OK > KL [br] Circle Center K with radius O, get points two points n, p[br] Circle Center n radius np[br] Circle Center p radius np, get q[br] Draw qK