# The radius of the sphere $x^2+y^2+z^2=12 x +4y+3z$ is :

$\begin {array} {1 1} (1)\;\frac{13}{2} & \quad (2)\;13 \\ (3)\;26 & \quad (4)\;52 \end {array}$

$(1)\;\frac{13}{2}$