\input{preamble-standalone.ltx} \begin{document} % Ex. No. 249 (Section 31.3.2 : Another example of of\tkzcname{tkzSetUpCompass}) \begin{tikzpicture}[scale=1,rotate=90] \tkzDefPoints{0/1/A, 8/3/B, 3/6/C} \tkzDrawPolygon(A,B,C) \tkzSetUpCompass[color=brown, line width=.3 pt,style=tkzdotted] \tkzDefLine[bisector](B,A,C) \tkzGetPoint{a} \tkzDefLine[bisector](C,B,A) \tkzGetPoint{b} \tkzInterLL(A,a)(B,b) \tkzGetPoint{I} \tkzDefPointBy[projection= onto A--B](I) \tkzGetPoint{H} \tkzMarkRightAngle(I,H,A) \tkzDrawCircle[radius,color=red](I,H) \tkzDrawSegments[color=red](I,H) \tkzDrawLines[add=0 and -.5,,color=red](A,a) \tkzDrawLines[add=0 and 0,color=red](B,b) \tkzShowLine[bisector,size=2,gap=3](B,A,C) \tkzShowLine[bisector,size=1,gap=3](C,B,A) \tkzLabelPoints(A,B)\tkzLabelPoints[left](C) \end{tikzpicture} \end{document}