| $$ \begin{aligned}5\sqrt{2025}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}5\cdot45 \xlongequal{ } \\[1 em] & \xlongequal{ }225\end{aligned} $$ | |
| ① | The square root of $ 2025 $ is $ 45 $. |