Rabbi Nehemiah

Rabbi Nehemiah was an Israelite mathematician, circa AD 150 (during the Tannaim era, Fourth Generation).
He is attributed as the author of the Mishnat ha-Middot (ca. AD 150), making it the earliest known Hebrew text on geometry, although some historians assign the text to a later period by an unknown author.
The Mishnat ha-Middot argues against the common belief that the Bible defines the geometric ratio π (pi) as being exactly equal to 3, based on the description in 1 Kings 7:23 (and 2 Chronicles 4:2) of the great bowl situated outside the Temple of Jerusalem as having a diameter of 10 cubits and a circumference of 30 cubits. He maintained that the diameter of the bowl was measured from the outside brim, while the circumference was measured along the inner brim, which with a brim that is one handbreadth wide (as described in the subsequent verses 1 Kings 7:24 and 2 Chronicles 4:3) yields a ratio from the circular rim closer to the actual value of π.