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# Round vs. Square

41 replies to this topic

### #11 mathemagister

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Posted 24 July 2007 - 09:21 AM

They condiam coins are the 20p and 50p ones.
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### #12 eyenine

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Posted 15 August 2007 - 02:13 PM

a triangle shaped cover wouldnt fall into a triangle shapped hole either
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### #13 willy

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Posted 15 August 2007 - 08:23 PM

a triangle shaped cover wouldnt fall into a triangle shapped hole either

i was about to say this however i should add that it's only an equilateral triangle that won't fall through.
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### #14 MrAscii

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Posted 15 August 2007 - 08:42 PM

a triangle shaped cover wouldnt fall into a triangle shapped hole either

i was about to say this however i should add that it's only an equilateral triangle that won't fall through.

While you could create a cover/hole combination where a triangle wouldn't fall through, it is not a certainty.

It all depends on the lip width and thickness of the cover material.

An equilateral triangle has a maximum diameter (the length of a side) that is ~1.15 times the minimum diameter (center of a side to the opposite vertex).

```______
|		  /
|		/
x	  /
|_   /___________
|--1.15x--|
- Dimensions```
So as long as the lip isn't too wide and the cover isn't too thick, it will fall through. Turn the cover so a one side of the triangle is vertical and the bottom or top is flat against a side of the hole.
```/|
/   |
/	  |
|
|
|
~~~~~~~~~~~~
(long side of hole)
- Side view

/		<- hole
/
/
/ ==========	<- cover (===)
~~~~~~~~~~~~~~~~
-Top view```

In any non-equilateral triangle the ratio of maximum diameter to minimum diameter gets larger and it is easer to fit the cover through the hole.

(sorry for the ugly drawings)
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### #15 Dillon

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Posted 15 August 2007 - 10:22 PM

Well, I'd imagine because you can't fit a square into a circle.

And if they didn't have a manhole itself as a circle, and had it as a square, maybe it wouldn't be right because people who climb down there are generally fat? No idea on that one there.
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### #16 Joseph_

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Posted 15 September 2007 - 04:37 PM

ahhh this is the stupidest question ever!
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### #17 credels

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Posted 19 September 2007 - 10:35 PM

Its round either because people are round, and its easier to traverse, or that pointy manhole covers would bend/break.

-=society works cause we think it does=-
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### #18 beej

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Posted 17 October 2007 - 02:51 PM

There are many answers I believe some of them are of which is they are safer with no points/verticies to poke people. Fits in any orientation, square won't if you rotate them 45 degrees. As well as the others already mentioned
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### #19 swimmingyrl555

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Posted 01 December 2007 - 05:27 PM

i have the perfect answer. they arent square so you dont stub your feet on them if they stick up too much.

lol!!

oh and haha i though this was a messed up face not a lightbulb haha
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### #20 TheChaos92

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Posted 24 December 2007 - 04:42 PM

square would be better in my oppion because you can put hinges on it easily.
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