From India
Baudhayana
His Shulba Sutra, a manual for building fire altars, states the rule about right-angled triangles that we now name after Pythagoras.
The Shulba Sutras give √2 ≈ 577/408, correct to five decimal places.
Where you’ll meet Baudhayana here
GeometryHistory
They turn up beside problems and lessons on these topics.
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Aryabhata
At 23 he wrote the Aryabhatiya (499 CE), a book in verse that gives π as 62832 ÷ 20000 = 3.1416.
India’s first satellite, launched in 1975, was named after him.
A modern statue; no likeness from his lifetime survives. Cpjha13, CC BY-SA 4.0, via Wikimedia Commons (resized)