Finding the center of a circle

mickyd · Post by **mickyd** » Fri Oct 23, 2009 3:02 pm

reible posted a pretty classy way to find the center of a circle using a gorgeous brass Wood Lathe Center Finder.

Here's a much less classy (aka cheap) most of the time "close enough" version is you don't have anything as spectacular.
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Where the lines bisect is .........the center.

curiousgeorge · Post by **curiousgeorge** » Fri Oct 23, 2009 3:22 pm

Thanks, Mike. That is simple, easy to remember and a lot cheaper than having to buy a center finder.

mickyd · Post by **mickyd** » Fri Oct 23, 2009 3:50 pm

curiousgeorge wrote:Thanks, Mike. That is simple, easy to remember and a lot cheaper than having to buy a center finder.

Then there is the good old "eyeball" method. No photos needed to demonstrate that!!

I think I'll just have to try that vs. the geometry method above just to see how close I can get.

charlese · Post by **charlese** » Fri Oct 23, 2009 3:54 pm

mickyd wrote:Then there is the good old "eyeball" method. No photos needed to demonstrate that!! I think I'll just have to try that vs. the geometry method above just to see how close I can get.

My experience is this method works better with larger circles, and with smaller ones it doesn't matter as much anyway.

fjimp · Post by **fjimp** » Fri Oct 23, 2009 4:43 pm

You folks are far classier than I am. I just measure across the widest point of the circle with my tape measure that once you read the width shows the center or 1/2 way point for that particular length. fjimp

Ed in Tampa · Post by **Ed in Tampa** » Sat Oct 24, 2009 12:16 am

It depends on what I want the center for. If I need to be real precise I use a compass set to a radius that is larger than the circle. I make two marks on the circle and then move the compass to make two more marks. I connect the first set of marks where they touch the circle and then the second set. Where these lines cross is the exact center of the circle.

rdewinter · Post by **rdewinter** » Sat Oct 24, 2009 9:33 am

I wish I would have known how my geometry studies could come in handy some day. It's sad that I forgot (or maybe I didn't study hard enough) so much of my mathematics. Thanks for the great tip Mike.

Bob
San Diego

dusty · Post by **dusty** » Sat Oct 24, 2009 11:30 am

rdewinter wrote:I wish I would have known how my geometry studies could come in handy some day. It's sad that I forgot (or maybe I didn't study hard enough) so much of my mathematics. Thanks for the great tip Mike.

Bob
San Diego

That is so true and I think universally applicable. If only my geometry and algebra teachers had known how to show me that this stuff was going to help me to do something other than graduate.

I refer to a high school math book probably once a week (at least).

mickyd · Post by **mickyd** » Sat Oct 24, 2009 12:20 pm

dusty wrote:That is so true and I think universally applicable. If only my geometry and algebra teachers had known how to show me that this stuff was going to help me to do something other than graduate.

I refer to a high school math book probably once a week (at least).

Is that school book on a papyrus scroll or carved in stone? I am not sure what the technology was back in those days

. (sorry dusty...I just couldn't resist!!)

JPG · Post by **JPG** » Sat Oct 24, 2009 1:17 pm

mickyd wrote:Is that school book on a papyrus scroll or carved in stone? I am not sure what the technology was back in those days . (sorry dusty...I just couldn't resist!!)

Maybe mike should run over to Bob's place and tutor him(refresh his math memories)!:p

BTW This older than Dusty person does NOT recall any of those ancient objects in HIS school days except in books of a historical bent. We didn't use wax tablets and stylus either!:rolleyes: