A new NCERT Class 8 mathematics textbook states that ancient Indian mathematician Baudhayana, around 800 BCE, first formulated the theorem on right-angled triangles, now commonly known as the Pythagorean Theorem. The textbook cites verses from Baudhayana's Sulba Sutra, detailing his understanding of the relationship between a square's diagonal and its area, and providing integer sets that satisfy the theorem. It notes that Greek mathematician Pythagoras, who lived centuries later, also studied this theorem, sometimes leading to its dual naming.