Comment by srean

It seems obvious now only because of significant mathematical discoveries of prominent mathematicians.

If one is taught what those discoveries revealed then of course they would seem obvious.

Arguing as you are, it would appear one can call all and every theorem in mathematics that connects to different fields as something obvious. They weren't, till someone proved the connection and that knowledge percolated down to how maths is taught, to text books.

That the integral of

        exp(-x*x) 

over the entire real line is sqrt pi can be surprising or obvious depending on how you were taught. At face value it has nothing to do with circles, unless you are taught the connection or you are a mathematician of high calibre who can see it without being taught the background information.