Answer
$\color{blue}{12}$
Work Step by Step
RECALL:
(1) For $a\gt0$ and $b\gt0$,
$\sqrt{a} \cdot \sqrt{b} = \sqrt{ab}$
(2) For $a\ge0$, $\sqrt{a^2} = a$
Use rule (1) above to obtain:
$\sqrt{6} \cdot \sqrt{24}
\\=\sqrt{6\cdot24}
\\=\sqrt{144}
\\=\sqrt{12^2}$
Use rule (2) above to obtain:
$=\color{blue}{12}$