Sajad

4 / √84  =

4 / √ [ 4 * 21 ]   =

4 /  [ 2 √21  ]   =

2 / √21

\(\frac{4}{\sqrt{84}}\)

\(\frac{4}{\sqrt{4\times21}}\)

\(\frac{4}{\sqrt{4}\sqrt{21}}\)

\(\frac{4}{2\sqrt{21}}\)

\(\frac{4}{2\sqrt{21}}\frac{\times}{\times}\frac{\sqrt{21}}{\sqrt{21}}\)

\(\frac{4\sqrt{21}}{2\times21}\)

\(\frac{4\sqrt{21}}{42}\frac{÷}{÷}\frac{2}{2}\)

\(\frac{2\sqrt{21}}{21}\)

\(\frac{2\times 4.58257569495584...}{21}\)

\(\frac{9.16515138991168...}{21}\)

\(0.43643578047198476...\)