Evaluate
3\sqrt{5}\approx 6.708203932
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\sqrt{5}+2\sqrt{5}
Factor 20=2^{2}\times 5. Rewrite the square root of the product \sqrt{2^{2}\times 5} as the product of square roots \sqrt{2^{2}}\sqrt{5}. Take the square root of 2^{2}.
3\sqrt{5}
Combine \sqrt{5} and 2\sqrt{5} to get 3\sqrt{5}.
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