Question: Where did the formula for area of a circle come from?
Disambiguated questions and answers: question: Where and from who did the formula for area of a circle come from?
Where did Archimedes derive the formula for area of a circle come from?
From what literary work did the formula for area of a circle first come from?
answer: Archimedes
viewing the circle as the limit of a sequence of regular polygons
method of exhaustion,
The Measurement of a Circle
Natural Questions answer: Archimedes (from the Wikipedia article "Area of a circle")