$$ \begin{aligned}\sqrt{3}\cdot\sqrt{3}& \xlongequal{ }\sqrt{9} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}3\end{aligned} $$ | |
① | The square root of $ 9 $ is $ 3 $. |