Tap the blue circles to see an explanation.
$$ \begin{aligned}\sqrt{20}\cdot\sqrt{8}& \xlongequal{ }\sqrt{160} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}} \sqrt{ 16 \cdot 10 } \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}} \sqrt{ 16 } \cdot \sqrt{ 10 } \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}4\sqrt{10}\end{aligned} $$ | |
① | Factor out the largest perfect square of 160. ( in this example we factored out $ 16 $ ) |
② | Rewrite $ \sqrt{ 16 \cdot 10 } $ as the product of two radicals. |
③ | The square root of $ 16 $ is $ 4 $. |