| $$ \begin{aligned}\sqrt{11}\cdot\sqrt{11}& \xlongequal{ }\sqrt{121} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}11\end{aligned} $$ | |
| ① | The square root of $ 121 $ is $ 11 $. |