\input{preamble-standalone.ltx} \begin{document} % Ex. No. 243 (Section 31.1.1 : Example 1: change line width) \begin{tikzpicture} \tkzSetUpLine[color=blue,line width=1pt] \begin{scope}[rotate=-90] \tkzDefPoint(10,6){C} \tkzDefPoint( 0,6){A} \tkzDefPoint(10,0){B} \tkzDefPointBy[projection = onto B--A](C) \tkzGetPoint{H} \tkzDrawPolygon(A,B,C) \tkzMarkRightAngle[size=.4,fill=blue!20](B,C,A) \tkzMarkRightAngle[size=.4,fill=red!20](B,H,C) \tkzDrawSegment[color=red](C,H) \end{scope} \tkzLabelSegment[below](C,B){$a$} \tkzLabelSegment[right](A,C){$b$} \tkzLabelSegment[left](A,B){$c$} \tkzLabelSegment[color=red](C,H){$h$} \tkzDrawPoints(A,B,C) \tkzLabelPoints[above left](H) \tkzLabelPoints(B,C) \tkzLabelPoints[above](A) \end{tikzpicture} \end{document}