Tap the blue circles to see an explanation.
| $$ \begin{aligned}\frac{\sqrt{21}}{\sqrt{66}}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{\sqrt{21}}{\sqrt{66}}\frac{\sqrt{66}}{\sqrt{66}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}\frac{3\sqrt{154}}{66} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}\frac{\sqrt{154}}{22}\end{aligned} $$ | |
| ① | Multiply the numerator and denominator by the conjugate of the denominator . $$\color{blue}{ \sqrt{66}} $$. |
| ② | Multiply in a numerator. $$ \color{blue}{ \sqrt{21} } \cdot \sqrt{66} = 3 \sqrt{154} $$ Simplify denominator. $$ \color{blue}{ \sqrt{66} } \cdot \sqrt{66} = 66 $$ |
| ③ | Divide both numerator and denominator by 3. |