\begin{tikzpicture}
    \draw circle (3);
    \filldraw circle (1pt);
    \draw ({3 * cos(45)}, {3 * sin(45)})
          -- ({-3 * cos(45)}, {3 * sin(45)})
          -- ({-3 * cos(45)}, {-3 * sin(45)})
          -- ({3 * cos(45)}, {-3 * sin(45)})
           -- cycle;
            
    \coordinate (a) at ({3 * sqrt(6)/6}, {3 * sin(45)});
    \coordinate (b) at ({3 * cos(45 + 15)}, {3 * sin(45 + 15)});
    
    \draw[thick, dotted] (0, 0) -- (b);
    \filldraw (a) circle (1pt) (b) circle (1pt);
\end{tikzpicture}