English: Photograph of the Yale Babylonian Collection's Tablet YBC 7289 obverse and reverse (YPM BC 021354). This tablet shows an approximation of the square root of 2 (1 24 51 10 w: sexagesimal) using the Pythagorean theorem for an isosceles triangle. Yale Peabody Museum description: Round tablet. Obv drawing of square with diagonal and inscribed numbers; rev drawing of rectangle with inscribed diagonal but numbers badly preserved and unable to be restored; mathematical text, Pythagorean tablet. Old Babylonian. Clay. obv 10.