Tap the blue circles to see an explanation.
$$ \begin{aligned}\frac{\sqrt{20}}{7}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{ \sqrt{ 4 \cdot 5 } }{ 7 } \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{ \sqrt{ 4 } \cdot \sqrt{ 5 } }{ 7 } \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{2\sqrt{5}}{7}\end{aligned} $$ | |
① | Factor out the largest perfect square of 20. ( in this example we factored out $ 4 $ ) |
② | Rewrite $ \sqrt{ 4 \cdot 5 } $ as the product of two radicals. |
③ | The square root of $ 4 $ is $ 2 $. |