\input{preamble-standalone.ltx} \begin{document} % Ex. No. 201 (Section 29.2.2 : Circle and tangent) \begin{tikzpicture} \edef\alphaR{\fpeval{asin(2/3)}} \edef\xB{8-3*cos(\alphaR)} \tkzDrawX[noticks,label=$(d)$] \tkzDefPoint["$A$" above right](8,2){A} \tkzDefPoint[color=red,"$O$" above right](0,0){O} \tkzDefPoint["$B$" above left](\xB,4){B} \tkzDefLine[orthogonal=through B](A,B) \tkzGetPoint{b} \tkzDefPoint(1,0){i} \tkzInterLL(B,b)(O,i) \tkzGetPoint{B'} \tkzDrawSegment[line width=1pt](A,B) \tkzHLine[color=red,style=dashed]{4} \tkzText[above](12,4){$\delta$} \tkzDrawCircle[R,color=blue,line width=.8pt](A,3 cm) \tkzDrawPoint(B') \tkzDrawLine(B,B') \end{tikzpicture} \end{document}