In this article, we study complete surfaces
$\sum $, isometrically immersed in the product spaces
${{\mathbb{H}}^{2}}\,\times \,\mathbb{R}$ or
${{\mathbb{S}}^{2\,}}\times \,\mathbb{R}$ having positive extrinsic curvature
${{K}_{e}}$. Let
${{K}_{i}}$ denote the intrinsic curvature of
$\sum $. Assume that the equation
$a{{K}_{i\,}}\,+\,b{{K}_{e\,}}\,=\,c$ holds for some real constants
$a\,\ne \,0$,
$b\,>\,0$, and
$c$. The main result of this article states that when such a surface is a topological sphere, it is rotational.