Find the equation of the radius of the circle $x^2-4x-6y+y^2=23$ and passing through the point $(4,5)$.
My attempt: Here the equation of the circle is: $$x^2-4x-6y+y^2=23$$ $$(x-2)^2+(y-3)^2=6^2$$ hence, center$$(h,k)=(2,3)$$ and radius$$r=6units$$. Now, what should I do next?