Baudhayana

The Baudhāyana sūtras are a group of Vedic Sanskrit texts which cover dharma, daily ritual, mathematics, etc. They belong to the Taittiriya branch of the Krishna Yajurveda school and are among the earliest texts of the genre, perhaps compiled in the 8th to 6th centuries BCE.The Baudhayana sūtras consist of six texts:

the Śrautasûtra, probably in 19 Praśnas (questions),
the Karmāntasûtra in 20 Adhyāyas (chapters),
the Dvaidhasûtra in 4 Praśnas,
the Grihyasutra in 4 Praśnas,
the Dharmasûtra in 4 Praśnas and
the Śulbasûtra in 3 Adhyāyas.The Baudhāyana Śulbasûtra is noted for containing several early mathematical results, including an approximation of the square root of 2 and the statement of the Pythagorean theorem.