#### Answer

$\frac{\sqrt {3x}}{6}$

#### Work Step by Step

$\sqrt \frac{x}{12}$
=$\frac{\sqrt x}{\sqrt {12}}$
=$\frac{\sqrt x}{\sqrt {4\times3}}$
=$\frac{\sqrt x}{2\sqrt {3}}$
=$\frac{\sqrt x}{2\sqrt {3}}\times\frac{2\sqrt {3}}{2\sqrt {3}}$
=$\frac{\sqrt x \times2\sqrt {3} }{2\sqrt {3}\times2\sqrt {3}}$
=$\frac{2\sqrt {3x}}{4(3)}$
=$\frac{\sqrt {3x}}{2(3)}$
=$\frac{\sqrt {3x}}{6}$