LaTeX-examples/documents/GeoTopo/figures/geometry-4.tex

\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}