\begin{tikzpicture}[scale=0.5]
	
		\node [style=bullet] (0) at (-3.25, 0) {};
		\node [style=bullet] (1) at (-1, 4) {};
		\node [style=bullet] (2) at (1.5, 0) {};
		\node [style=bullet small] (3) at (-2.25, 1.25) {};
		\node [style=bullet small] (4) at (-1.75, 0.25) {};
% 		\node [] (5) at (-3.75, -0.5) {$i$};
% 		\node [] (6) at (-1, 4.75) {$k$};
% 		\node [] (7) at (2, -0.5) {$j$};
		\node [] (8) at (-1, 1.5) {$\theta$};
	
		\draw (0) to node [above left] {$a$} (1);
		\draw (1) to node [above right] {$b$} (2);
		\draw (2) to node [below] {$c$} (0);
		\draw [style=red 1, bend left] (3) to (4);

\end{tikzpicture}
