Tap the blue circles to see an explanation.
$$ \begin{aligned}\frac{15}{4\sqrt{5}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{15}{4\sqrt{5}}\frac{\sqrt{5}}{\sqrt{5}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{15\sqrt{5}}{20} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{ 15 \sqrt{ 5 } : \color{blue}{ 5 } } { 20 : \color{blue}{ 5 }} \xlongequal{ } \\[1 em] & \xlongequal{ }\frac{3\sqrt{5}}{4}\end{aligned} $$ | |
① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ \sqrt{5}} $$. |
② | Multiply in a numerator. $$ \color{blue}{ 15 } \cdot \sqrt{5} = 15 \sqrt{5} $$ Simplify denominator. $$ \color{blue}{ 4 \sqrt{5} } \cdot \sqrt{5} = 20 $$ |
③ | Divide numerator and denominator by $ \color{blue}{ 5 } $. |