If an equilateral triangle is inscribed in the circle $x^2+y^2-6x-4y+5=0$ then length of its side is 
 

The given circle is $x^2+y^2-6x-4y+5=0$

Radius of the circle is 

         $\begin{array}{rcl}r& =& \sqrt{g^2+f^2-c}\\ & =& \sqrt{9+4-5}\\ & =& \sqrt{8}\\ & =& 2\sqrt{2}\end{array}$

Length of side of an equilateral triangle which is inscribed in a circle of radius $r$ is $\sqrt{\mathbf{3}}\mathit{r}$

Therefore, the length of the side of equilateral triangle is $\sqrt{3}\left(2\sqrt{2}\right)=\boxed{2\sqrt{6}}$