Answer
$\displaystyle \log_{5}\sqrt{5}=\frac{1}{2}$.
Work Step by Step
For $a>0, a\neq 1$, and $x>0,\qquad y=\log_{a}x$ means $a^{y}=x$.
$.................................$
$ 5^{1/2}=\sqrt{5} \qquad$ means the same as
$\displaystyle \log_{5}\sqrt{5}=\frac{1}{2}$.
