Evaluate
\frac{2\sqrt{21}}{21}\approx 0.43643578
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\frac{2\sqrt{21}}{\left(\sqrt{21}\right)^{2}}
Rationalize the denominator of \frac{2}{\sqrt{21}} by multiplying numerator and denominator by \sqrt{21}.
\frac{2\sqrt{21}}{21}
The square of \sqrt{21} is 21.
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