#### Answer

There were around $378.0$ million cellular phone users in the United States in 2012.

#### Work Step by Step

WE have to assume that the given equation would still model the number of cell phone users after 2010
2012 is 10 years after 2002 so $x=10$. Substitute 10 to $x$ in the equation to have:
$\\y=136.76(1.107)^x
\\y=136.76(1.107)^{10}
\\y=377.9508278
\\y\approx 378.0$