Incircle[A,B,C]
A,B,C the vertices of the triangle,
Gives
[math]\;\;\;[/math]Inscribed circle (incircle)
[math]\;\;\;[/math]Circle center (incenter)
[math]\;\;\;[/math]Points of tangency to the triangle.
Construction: [url]http://www.geogebratube.org/material/show/id/88096[/url]