$$ \begin{aligned}\frac{\sqrt{2}}{\sqrt{5}^2}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{\sqrt{2}}{5}\end{aligned} $$ | |
① | $$ \sqrt{5}^2 =
\sqrt{5} ^2 =
\lvert 5 \rvert =
5 $$ |