LaTeX-examples/documents/GeoTopo/figures/three-angles.tex

\begin{tikzpicture}
    \tkzSetUpPoint[shape=circle,size=10,color=black,fill=black]
    \tkzSetUpLine[line width=1]
    \tkzDefPoints{0/0/P, 1/0/helperRight, 1/1/helperTopRight, -1/1/helperTopLeft, -1/0/helperLeft, -1/-0.3/helperBottomLeft}

    \tkzMarkAngle[arc=l,size=0.8cm,color=green,fill=green!20](helperRight,P,helperTopRight)
    \tkzMarkAngle[arc=ll,size=0.8cm,color=blue,fill=blue!20](helperTopRight,P,helperTopLeft)
    \tkzMarkAngle[arc=lll,size=0.8cm,color=red,fill=red!20](helperTopLeft,P,helperBottomLeft)
    \path[draw] ++(25:.4) node[rotate=0] {$\alpha$};
    \path[draw] ++(90:.4) node[rotate=0] {$\beta$};
    \path[draw] ++(160:.4) node[rotate=0] {$\gamma$};

    \tkzDrawLine[add=0 and 1.0](P, helperRight)
    \tkzDrawLine[add=0 and 0.3](P, helperTopRight)
    \tkzDrawLine[add=0 and 0.3](P, helperTopLeft)
    \tkzDrawLine[add=0 and 1.0](P, helperLeft)
    \tkzDrawLine[add=0 and 0.8](P, helperBottomLeft)

    \tkzDrawPoints(P)
    \tkzLabelPoint[below](P){$P$}
\end{tikzpicture}