\usetikzlibrary{positioning}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{shapes.misc}

\begin{tikzpicture}[scale=1]

    \draw[very thick] (0,0) circle (1.25cm) ;
    \node[regular polygon, regular polygon sides=6, shape aspect=0.5, minimum width=4cm, minimum height=1cm, draw,scale=0.75, very thick] (reg) {2.5cm};

\end{tikzpicture}
