Calculer les longueurs $HE$ et $HD$

\begin{center}
    \includegraphics{./fig/situation_thales}
\end{center}

.\dotfill \\[0.3cm]
.\dotfill \\[0.3cm]
.\dotfill \\[0.3cm]
.\dotfill \\[0.3cm]
.\dotfill \\[0.3cm]
.\dotfill \\[0.3cm]
.\dotfill \\[0.3cm]
.\dotfill \\[0.3cm]
.\dotfill \\[0.3cm]
