Question

who discovered 2 Pi R​

Answer 1

Here Is Your Ans

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Formula of Circumference of circle was invented by Archimedes

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Answer 2

$\mathfrak{The\:Answer\:is}$

$i \: hope \: you \: mean \: \pi \times r {}^{2}$

which was discovered by the Babylonians.

$\boxed{Hope\:This\:Helps}$