\begin{tikzpicture} \tkzSetUpPoint[shape=circle,size=10,color=black,fill=black] \tkzSetUpLine[line width=1] \tkzDefPoints{0/0/P, 4/1/Q, 2/3/A, 0/3/B} \tkzDrawSegments(P,Q Q,A A,P) \tkzDrawSegments[dashed](P,B B,Q) \tkzDrawLine(P,Q) \tkzDrawLine[color=red](P,A) \tkzDrawPoints(P,C,A) \tkzDrawPoints[fill=red,color=red](Q,B) \tkzLabelPoint[below](P){$P$} \tkzLabelPoint[below](Q){$Q$} \tkzLabelPoint[above](A){$A$} \tkzLabelPoint[above](B){$B$} \end{tikzpicture}