The area of a circle is pi(r^2), however, there is another
relationship, specifically d^2 (.785) to arrive at the same answer.

The .785 comes from an approximation of pi/4, which is apparently
derived from a circle inscribed within a square.

My question is, how does one arrive at pi/4 by incribing a circle in a
square?  There are a lot of web references on incribing a square
within a circle, but not the other way around.

Thanks in advance!

Herkdrvr

They are the same formula:

r = d/2

r^2 = (d/2)^2 = d^2/4

Redhoss has answered the formula part of the question.

I notice that you're asking about a circle in a square also...  I'm
not sure what that has to do with the rest of your question since
you've already determined that the diameter is d.  So whether the
circle is in a square or not, the diameter is the same.

Sheesh...I knew it was simpler than I was making it.


Thanks!