\begin{tikzpicture}[scale=0.75] \tkzDefPoint(0,0){A} \tkzDefPoint(4,0){B} \tkzDefPoint(3,3){C} \tkzDefCircle[in](A,B,C) \tkzGetPoint{I}\tkzGetLength{rI} \tkzDrawCircle[R](I,\rI) \tkzDrawPolygon(A,B,C) \tkzDrawPoints(A,B,C,I) \tkzLabelPoints(A,B,C,I) \end{tikzpicture}