(5) - Outcoming

$\text{M}$ and $\text{N}$ are points respectively on line segment $\text{BC}$ and $\text{CD}$ of $\square{\text{ABCD}}$ , side $a$ such that $\text{MC} = 6$ and $\text{CN} = 8$ . If $\text{MN}$ is a tangent of $(\text{A}, a)$ at $\text{P}$ , the value of $\text{CP}$ is $\dfrac{m}{\sqrt n}$ with $n$ is square - free. What is the value of $\dfrac{m}{n^2}$ .