\input{preamble-standalone.ltx}
\begin{document}

% Ex. No. 210 (Section 25.2.1 : Compass square construction)

\begin{tikzpicture}[scale=1]
  \tkzDefPoint(0,0){A} \tkzDefPoint(4,0){B}
  \tkzDrawLine[add= .6 and .2](A,B)
  \tkzCalcLength[cm](A,B)\tkzGetLength{dAB}
  \tkzDefLine[perpendicular=through A](A,B)
  \tkzDrawLine(A,tkzPointResult) \tkzGetPoint{D}
  \tkzShowLine[orthogonal=through A,gap=2](A,B)
  \tkzMarkRightAngle(B,A,D)
  \tkzVecKOrth[-1](B,A)\tkzGetPoint{C}
  \tkzCompasss(A,D D,C)
  \tkzDrawArc[R](B,\dAB)(80,110)
  \tkzDrawPoints(A,B,C,D)
  \tkzDrawSegments[color=gray,style=dashed](B,C C,D)
  \tkzLabelPoints(A,B,C,D)
\end{tikzpicture}

\end{document}