Answer
$\dfrac{1}{2}$
Work Step by Step
Note that $y = \ln{x} \text{ is equivalent to } x=e^y$.
Thus if $y=\ln{\sqrt{e}}$, then $e^y=\sqrt{e}$.
Since $\sqrt{e} = e^{\frac{1}{2}}$, then
$e^y = e^{\frac{1}{2}}$
Use the rule $a^m=a^n \implies m=n$ to obtain:
$y=\dfrac{1}{2}$
Therefore,
$\ln{\sqrt{e}} = \boxed{\dfrac{1}{2}}$
