\input{preamble-standalone.ltx} \begin{document} % Ex. No. 43 (Section 9.4.1 : Example of symmetry) \begin{tikzpicture}[scale=1.5] \tkzDefPoint(0,0){O} \tkzDefPoint(2,-1){A} \tkzDefPoint(2,2){B} \tkzDefPointsBy[symmetry=center O](B,A){} \tkzDrawLine(A,A') \tkzDrawLine(B,B') \tkzMarkAngle[mark=s,arc=lll, size=2 cm,mkcolor=red](A,O,B) \tkzLabelAngle[pos=1,circle,draw, fill=blue!10](A,O,B){$60^{\circ}$} \tkzDrawPoints(A,B,O,A',B') \tkzLabelPoints(A,B,O,A',B') \end{tikzpicture} \end{document}