Tap the blue circles to see an explanation.
$$ \begin{aligned}4\sqrt{243}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}4\cdot \sqrt{ 81 \cdot 3 } \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}4\cdot \sqrt{ 81 } \cdot \sqrt{ 3 } \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}4\cdot9 \sqrt{ 3 } \xlongequal{ } \\[1 em] & \xlongequal{ }36\sqrt{3}\end{aligned} $$ | |
① | Factor out the largest perfect square of 243. ( in this example we factored out $ 81 $ ) |
② | Rewrite $ \sqrt{ 81 \cdot 3 } $ as the product of two radicals. |
③ | The square root of $ 81 $ is $ 9 $. |