\documentclass[varwidth=true, border=2pt]{standalone} \usepackage{tkz-euclide} \begin{document} \usetkzobj{all} \begin{tikzpicture} \tkzSetUpPoint[shape=circle,size=10,color=black,fill=black] \tkzSetUpLine[line width=1] \tkzDefPoints{0/0/Q, 4/1/H1, 1/2/P} \tkzDefPoint(1.5,3){Phelper} \tkzMarkAngle[arc=l,size=1cm,color=green,fill=green!20](H1,Q,P) \tkzDrawLine(Q,H1) \tkzLabelPoint[above left](Q){$Q$} \tkzDefLine[parallel=through P](Q,H1) \tkzGetPoint{b} \tkzMarkAngle[arc=l,size=1cm,color=green,fill=green!20](b,P,Phelper) \tkzDrawLine[dashed](P,b) \tkzLabelLine[pos=0.8,below](P,b){$h$} \tkzLabelLine[pos=-0.6,left](P,Q){$f$} \tkzLabelLine[pos=0.8,below](Q,H1){$g$} \tkzLabelPoint[above left](P){$P$} \tkzDrawLine[add=0.2 and 0.7](Q,P) \tkzDrawPoints(P,Q) \tkzMarkSegments[mark=||](Q,H1 P,b) \end{tikzpicture} \end{document}