# How do you simplify sqrt4/(2sqrt20)?

Feb 8, 2017

We may start by realizing that $20 = 4 \times 5$
$= \frac{\cancel{\sqrt{4}}}{2 \cdot \cancel{\sqrt{4}} \cdot \sqrt{5}} = \frac{1}{2 \sqrt{5}}$
To make it look better, we multiply by $1$, disguised as $\frac{\sqrt{5}}{\sqrt{5}}$
$= \frac{1}{2 \sqrt{5}} \times \frac{\sqrt{5}}{\sqrt{5}} = \frac{\sqrt{5}}{2 {\sqrt{5}}^{2}} = \frac{\sqrt{5}}{2 \cdot 5} = \frac{1}{10} \sqrt{5}$