We are given two equations of circles:
1. \( (x - 1)^2 + (y - 3)^2 = r^2 \), which represents a circle with center \( (1, 3) \).
2. \( x^2 + y^2 - 8x + 2y + 8 = 0 \), which we simplify to find the equation of the second circle.
After simplifying the second circle's equation, we find the radius \( r \), and based on the relationship, the final result gives \( 2 < r < 8 \).