\begin{exercice}
  Parmi les constructions ci-dessous, lesquelles
  concernent des suites g\'{e}om\'{e}triques ?
  \begin{enumerate}
  \item ~\par\includestandalone{\pathmanuel/figures/img-21}\par
  \item ~\par\includestandalone{\pathmanuel/figures/img-22}\par\columnbreak
  \item ~\par\centerline{\includestandalone{\pathmanuel/figures/img-23}}\par
  \item ~\par\includestandalone{\pathmanuel/figures/img-24}
  \end{enumerate}
\end{exercice}
% \begin{corrige}
%   La repr\'{e}sentation \textbf{a)}.  
% \end{corrige}
