如图,\(D\),\(E\)分别为\(\triangle ABC\)的边\(AB\),\(AC\)上的点,且不与\(\triangle ABC\)的顶点重合\(.\)已知\(AE\)的长为\(m\),\(AC\)的长为\(n\),\(AD\),\(AB\)的长是关于\(x\)的方程\(x^{2}-14x+mn=0\)的两个根.
\((\)Ⅰ\()\)证明:\(C\),\(B\),\(D\),\(E\)四点共圆;
\((\)Ⅱ\()\)若\(∠A=90^{\circ}\),且\(m=4\),\(n=6\),求\(C\),\(B\),\(D\),\(E\)所在圆的半径.