\begin{tikzpicture} \tkzSetUpPoint[shape=circle,size=10,color=black,fill=black] \tkzSetUpLine[line width=1] \tkzDefPoints{0/0/A, 4/0/B, -2/3/C} \tkzDefLine[orthogonal=through A,/tikz/overlay](B,C) \tkzGetPoint{helper} \tkzInterLL(B,C)(A,helper) \tkzGetPoint{La} \tkzMarkAngle[arc=l,size=0.4cm,color=red,fill=red!20](A,La,B) \tkzLabelAngle[pos=0.25](A,La,B){$\cdot$} \tkzDrawPolygon(A,B,C) \node at ($(A)+(-0.47,-0.2)$){$A$}; \node at ($(B)+(0.35,-0.2)$) {$B$}; % \tkzLabelPoint[below](B){$B$} is not accurate enough \node at ($(C)+(0.05,0.3)$) {$C$}; \node[green] at ($(La)+(-0.4,-0.1)$) {$L_A$}; \tkzDrawSegments[red](A,La) \tkzDrawSegments[blue](B,C) \tkzLabelSegment[right,red](A,La){$h_a$} \tkzLabelSegment[above,blue](B,C){$c$} \tkzDrawPoints(A,B,C) \tkzDrawPoints[color=green,fill=green](La) \end{tikzpicture}