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Circles to make a pentagon


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17 replies to this topic

#11 BMAD

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Posted 28 February 2014 - 04:34 PM

tslf, you have me worried.  For I have done it much the same way.  Let me re-examine my own solution as well.


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#12 bonanova

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Posted 01 March 2014 - 12:01 AM

Spoiler for

 

@BMAD my pentagon solution seems inaccurate.I found out the side length point at (+) being off . I would like to request your better solution for im having trouble with finding the last point of side length.

 

Spoiler for Here is a rather well known construction that the OP may or may not permit


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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
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#13 BMAD

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Posted 01 March 2014 - 04:15 PM

Spoiler for pentagon solution

Edited by BMAD, 01 March 2014 - 04:16 PM.

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#14 TimeSpaceLightForce

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Posted 02 March 2014 - 05:48 AM

circus.GIF

Thanks!


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#15 BMAD

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Posted 02 March 2014 - 01:32 PM

lol


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#16 BMAD

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Posted 02 March 2014 - 01:33 PM

Can you construct a heptagon without assuming you can make several linear points?


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#17 phil1882

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Posted 02 March 2014 - 03:47 PM

well constructing linear points is a valid part of a compass.

simply construct a circle, and mark the point you left off on, or if you can't do that,

pick a point on the circle, draw a circle keeping the compass the same radius.

then from one of the points of intersection, construct another circle. the two newest circles meet in the middle.

and then most new and the first circle meet, you can then construct another  point using a similar process

for a pentagon, you can use the golden ratio, (1+sqrt(5))/2. which is easy enough to construct.

with a heptagon, its impossible. see http://en.wikipedia.org/wiki/Heptagon


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#18 BMAD

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Posted 02 March 2014 - 10:36 PM

I was under the same impression Phil regarding the Heptagon, which is why i asked in the op  :thumbsup:  (a possible and impossible solution).  Thanks for the link and thank you for explaining the construction of linear points.  I missed that part  :blush: .


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