Answer
$$128\pi*cm^2/min$$
Work Step by Step
We can write the surface area as,
$$A = 4*\pi*r^2$$
Taking the derivative of both sides with respect to t,
$$dA/dt = 8\pi r*dr/dt$$
We know $dr/dr$ is 2 cm/min, and $r=8 cm$. Plugging those in,
$$dA/dt = 8*\pi*8*2 cm^2/min = 128\pi*cm^2/min$$
