\usetkzobj{all} \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, 5/3/B, -0.6/-0.15/Pstrich} \tkzInterLL(P,B)(A,Q) \tkzGetPoint{C} \tkzDrawPoints(P,Q,A,B,C,Pstrich) \tkzDrawLine(P,Q) \tkzDrawLine(P,A) \tkzDrawLine(A,Q) \tkzDrawLine(P,B) \tkzLabelPoint[below](P){$P$} \tkzLabelPoint[above](Pstrich){$P'$} \tkzLabelPoint[below](Q){$Q$} \tkzLabelPoint[below](A){$A$} \tkzLabelPoint[below](B){$B$} \tkzLabelPoint[above](C){$C$} \end{tikzpicture}