Læresætningen er opkaldt efter [[Pythagoras]]. [[Princip]]pet var velkendt både for [[egypt]]ere og [[babylonere]]<ref>[https://www.economist.com/science-and-technology/the-babylonians-used-pythagorean-ideas-long-before-pythagoras/21803301 Aug 5th 2021, economist.com: The Babylonians used Pythagorean ideas long before Pythagoras. Surveyors employed them to measure out land], [https://web.archive.org/web/20230727165302/https://www.economist.com/science-and-technology/the-babylonians-used-pythagorean-ideas-long-before-pythagoras/21803301 backup]: Citat: "...MOST READERS will have encountered Pythagoras’s theorem about right-angled triangles—that the square on the hypotenuse is equal to the sum of the squares on the other two sides—at school. But the less-mathematically inclined might have been tempted to ask when such knowledge would ever be useful in real life. One answer, predating Pythagoras by over 1,000 years, is in land surveying...Lurking in a museum in Istanbul is a 3,700-year-old clay tablet known as Si.427. It has been there since it was dug up in the 19th century in Sippar, an ancient Babylonian city in what is now Iraq...What is remarkable is that its text describes the use of what are now called Pythagorean triples to draw accurate right angles..."</ref> længe før Pythagoras' tid, når det gjaldt en trekant med målene 3, 4 og 5; men Pythagoras beviste, at princippet gjaldt i ''alle'' tilfælde. <ref>Eiliv Skard: ''Filosofien i oldtiden'' (s. 40), forlaget Aschehoug, Oslo 1972, {{ISBN|82-03-00680-9}}</ref>
Matematik Matematiske_sætninger