Square root of 2 the square root of two, with a reasonable small denominator, the fraction (≈ 1.4142857) is sometimes used. The sequence in the OEIS gives the numerical value for the square root of two, truncated to 65 decimal places: The Babylonian clay tablet YBC 7289 (c. 1800–1600 BC) gives an approximation of in four sexagesimal figures, , which is accurate to about six decimal digits, and is the closest possible three-place sexagesimal representation of : Another early close approximation is given in ancient Indian mathematical texts, the Sulbasutras (c. 800–200 BC) as follows: "Increase the length [of the side] by its third
Square root of 2 Since it is a convergent of the continued fraction representation of the square root of two, any better rational approximation has a denominator not less than 169, since (≈ 1.4142012) is the next convergent with an error of approx. . The rational approximation of the square root of two, , derived from the fourth step in the Babylonian algorithm starting with , is too large by approx. : its square is … This is a table of recent records in calculating digits of A short proof of the irrationality of can be obtained from the rational root theorem, that is,