Answer
$\sqrt{\dfrac{3}{7}}=\dfrac{3}{\sqrt{21}}$
Work Step by Step
$\sqrt{\dfrac{3}{7}}$
Rewrite this expression as $\dfrac{\sqrt{3}}{\sqrt{7}}$:
$\sqrt{\dfrac{3}{7}}=\dfrac{\sqrt{3}}{\sqrt{7}}=...$
Multiply this fraction by $\dfrac{\sqrt{3}}{\sqrt{3}}$ and simplify if possible:
$...=\dfrac{\sqrt{3}}{\sqrt{7}}\cdot\dfrac{\sqrt{3}}{\sqrt{3}}=\dfrac{\sqrt{3^{2}}}{\sqrt{21}}=\dfrac{3}{\sqrt{21}}$