The diagrams shows a circle with radius $$r$$ with a straight line tangent to the circle, the straight line passes through the point $$A$$ and $$B$$. Given that $$C$$ is on the point of $$C$$. And the distances $$\overline{AC} = 4, \overline{BC} = 3, \overline{AB} = 5$$. Find the radius of the circle.