- Sum of two squares
In mathematics, sums of two squares occur in a number of contexts:

* The

Pythagorean theorem says that the square on the hypotenuse of a right triangle is equal in area to the sum of the squares on the legs

*Brahmagupta–Fibonacci identity says the set of all sums of two squares is closed under multiplication.

*Fermat's theorem on sums of two squares says which integers are sums of two squares.

** A separate article discussesProofs of Fermat's theorem on sums of two squares

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