Let the tangent to the circle $x ^ { 2 } + y ^ { 2 } = 25$ at the point $R ( 3,4 )$ meet $x$-axis and $y$-axis at point $P$ and $Q$, respectively. If $r$ is the radius of the circle passing through the origin $O$ and having centre at the incentre of the triangle $O P Q$, then $r ^ { 2 }$ is equal to\\
(1) $\frac { 529 } { 64 }$\\
(2) $\frac { 125 } { 72 }$\\
(3) $\frac { 625 } { 72 }$\\
(4) $\frac { 585 } { 66 }$