Fermat's Last Theorem - Wikipedia
https://en.wikipedia.org/wiki/Fermat's_Last_TheoremIn ancient times it was known that a triangle whose sides were in the ratio 3:4:5 would have a right angle as one of its angles. This was used in construction and later in early geometry. It was also known to be one example of a general rule that any triangle where the length of two sides, each squaredand then added together (3 + 4 = 9 + 16 = 25), equals the square of the length of the third side (…