Answer
$log_{625}5=\frac{1}{4}$
Work Step by Step
For all positive numbers $a$, where $a\ne1$, and all positive numbers $x$, we know that $y=log_{a}x$ means the same as $x=a^{y}$.
Therefore, $\sqrt[4] 625=625^{\frac{1}{4}}=5$ means the same as $log_{625}5=\frac{1}{4}$.