I wanted to know if this was correct because I don’t Quite get it

This is a special triangle which angles are 30-90-60, we can conclude the following:
Therefore, we can conclude that the hypotenuse is:
[tex]\begin{gathered} h=2x \\ h=2\cdot(3\sqrt[]{3}) \\ h=6\sqrt[]{3} \end{gathered}[/tex]Answer:
6√3