Fermat's right triangle theorem is, by the Pythagorean theorem, they would form two integer-sided right triangles in which the pair formula_10 gives one leg and the hypotenuse of the smaller triangle and the same pair also forms the two legs of the larger triangle. But if (as Fibonacci asserted) no square congruum can exist, then there can be no two integer right triangles that share two sides in this way. Because the congrua are exactly the numbers that are four times the area of a Pythagorean triangle, and multiplication by four does not change whether a number is square, the existence of a square
Manezhnaya Square, Saint Petersburg Manezhnaya Square, Saint Petersburg Manezhnaya Square (, romanized "Manezhnaya ploschad") ia a square in the Tsentralny District of Saint Petersburg. In some guidebooks this square may be also named a "Riding-School Square": "riding school" is one of the variants in which and may be translated. The shape of Manezhnaya Square is close to the right-angled triangle. Its longest cathetus, the southern side of Manezhnaya Square is formed with "Italyanskaya Street", which runs parallel to Nevsky Prospect, at about hundred meters north of it. The shortest cathetus is "Karavannaya Street", which forms the eastern side of the square running from Nevky