\input{preamble-standalone.ltx} \begin{document} % Ex. No. 64 (Section 10.1.5 : Option \tkzname{orthogonal} with $K=-1$) \begin{tikzpicture}[scale=.75] \tkzDefPoint(1,2){O} \tkzDefPoint(2,5){I} \tkzDefPointWith[orthogonal](O,I) \tkzGetPoint{J} \tkzDefPointWith[orthogonal,K=-1](O,I) \tkzGetPoint{K} \tkzDrawSegment(O,I) \tkzDrawSegments[->](O,J O,K) \tkzMarkRightAngles(I,O,J I,O,K) \tkzDrawPoints(O,I,J,K) \tkzLabelPoints(O,I,J,K) \end{tikzpicture} \end{document}