Between which two consecutive integers is sqrt(51)51 ?

1 Answer
Mar 5, 2017

7 < sqrt(51) < 87<51<8

Explanation:

Note that:

7^2 = 49 < 51 < 64 = 8^272=49<51<64=82

Hence:

7 < sqrt(51) < 87<51<8

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Bonus

Since 51 = 7^2+251=72+2 is of the form n^2+2n2+2, its square root takes a simple form as a continued fraction:

sqrt(51) = [7;bar(7,14)] = 7+1/(7+1/(14+1/(7+1/(14+1/(7+...)))))

We can use this continued fraction expansion to give us rational approximations for sqrt(51)

For example:

sqrt(51) ~~ [7;7] = 7+1/7 = 50/7 = 7.bar(142857)

sqrt(51) ~~ [7;7,14,7] = 7+1/(7+1/(14+1/7)) = 4999/700 = 7.14bar(142857)