\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}