Answer
8 feet
Work Step by Step
Recall that the surface area of a right circular cone is given by:
$\pi r^2 + \pi rs$
Since s equals the diameter of the base, we know that s equals $2r$, Thus:
$ SA = \pi r^2 + \pi r(2r) \\ 192 = r^2 + 2r^2 \\ 192 = 3r^2 \\ r = 8 $
