

Subject:
Area of a Circle = (d^2) x .785 where d = diameter...Why???
Category: Science > Math Asked by: herkdrvrga List Price: $5.00 
Posted:
07 Jul 2006 04:41 PDT
Expires: 07 Jul 2006 06:18 PDT Question ID: 744045 
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 

There is no answer at this time. 

Subject:
Re: Area of a Circle = (d^2) x .785 where d = diameter...Why???
From: redhossga on 07 Jul 2006 04:55 PDT 
They are the same formula: r = d/2 r^2 = (d/2)^2 = d^2/4 
Subject:
Re: Area of a Circle = (d^2) x .785 where d = diameter...Why???
From: jack_of_few_tradesga on 07 Jul 2006 05:41 PDT 
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. 
Subject:
Re: Area of a Circle = (d^2) x .785 where d = diameter...Why???
From: herkdrvrga on 07 Jul 2006 06:18 PDT 
Sheesh...I knew it was simpler than I was making it. Thanks! 
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