| $$ \begin{aligned}\frac{\sqrt{5}}{2}\sqrt{3}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{\sqrt{15}}{2}\end{aligned} $$ | |
| ① | $$ \color{blue}{ \sqrt{5} } \cdot \sqrt{3} = \sqrt{15} $$$$ \color{blue}{ 2 } \cdot 1 = 2 $$ |