# How do you simplify the square root of 45/125?

$\sqrt{\frac{45}{125}} = \frac{3}{5}$
If $a \ge 0$ then $\sqrt{{a}^{2}} = a$
$\sqrt{\frac{45}{125}} = \sqrt{\frac{5 \cdot 9}{5 \cdot 25}} = \sqrt{\frac{9}{25}} = \sqrt{{3}^{2} / {5}^{2}} = \sqrt{{\left(\frac{3}{5}\right)}^{2}} = \frac{3}{5}$