The center of the incircle is marked with point I. [br][br]This applet also introduces [u]excircles[/u]: when the sides of a triangle are extended, the excircles are circles that are tangent to the extended sides of the circle AND the third side of the triangle. [br][size=50][br]For funsies: How do you think you would construct an excircle? Open up another tab of geogebra.org/geometry and see if your idea works!!![/size]