| $$ \begin{aligned}2\sqrt{5}\cdot3\sqrt{30}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}30\sqrt{6}\end{aligned} $$ | |
| ① | $$ 6 \sqrt{150} =
6 \sqrt{ 5 ^2 \cdot 6 } =
6 \sqrt{ 5 ^2 } \, \sqrt{ 6 } =
6 \cdot 5 \sqrt{ 6 } =
30 \sqrt{ 6 } $$ |