Canada, 1 cent 1986

[Rangnath]

I refuse to research this myself, but here goes. 
1.  The Canadian coin has 12 sides.  Why? I would guess that sides were used to render them different from their American Cousin, but why 12 specially if Canada is a federation composed of ten provinces and three territories.  Why not 13?  Or 10? 
2.  How many sides does a coin, shaped like a polygon, have until it perceptually looks like a circle?  When I was a kid, I remember thinking that the Canadian penny looked like a polygon attempting to resemble a circle.
3. Which coin in the world is polygonal with the most sides?
richie

Edit: blackev's picture moved here. Original thread can be found here.

[translateltd]

I refuse to research this myself, but here goes. 
1.  The Canadian coin has 12 sides.  Why? I would guess that sides were used to render them different from their American Cousin, but why 12 specially if Canada is a federation composed of ten provinces and three territories.  Why not 13?  Or 10? 
2.  How many sides does a coin, shaped like a polygon, have until it perceptually looks like a circle?  When I was a kid, I remember thinking that the Canadian penny looked like a polygon attempting to resemble a circle.
3. Which coin in the world is polygonal with the most sides?
richie

1.  12 is quite a common choice for multi-sidedness (not sure if the UK 1937 3d was the first - that would be an interesting question in itself, but I know Canada adopted 12 sides for its nickel 5c coins in the 1940s).  3 sides is quite rare for circulating coins (Cook Is $2), 4 has been done (various Indian denominations), 5 (Yemen), 6 (Egypt), 7 (Britain et al.), 8 (Egypt again, also Maltese 25c?), 9 (somewhere - can't think off-hand), and I don't know whether ten or eleven have been done anywhere.

2 and 3.   My bet for the most multi-sided and almost circular coin would be the French 25 centimes of 1904-05, which looks circular until you examine it more closely - it's either 24 or 25 sides (I lost count when I tried many years ago).

[tonyclayton]

I refuse to research this myself, but here goes. 
1.  The Canadian coin has 12 sides.  Why? I would guess that sides were used to render them different from their American Cousin, but why 12 specially if Canada is a federation composed of ten provinces and three territories.  Why not 13?  Or 10? 

richie

The cent was made 12-sided in 1982 to assist those with impaired vision in trying to differentiate the cent and the 10 cent coins, which are only about 1 mm different in diameter.
In 1997 they reverted to round as the corners were not suitable for copper plating when the metal changed from bronze to copper plated zinc
An even number of edges is more logical except when the constant diameter feature of coins such as the UK 50p is required.
What their American cousins did was irrelevant!

[Rangnath]

Martin, thank you for the information.  HOLY COW!  I never knew the French 1904 25 Centime was NOT ROUND!!!!     

And thanks tonyclayton. You got me.     As an Ego centric American, I naturally assumed that whatever Canada does must be in reaction to the USA.  We American Cousins can be an arrogant lot!  As a way of apology, I offer Alaska to the Canadian Government, as long as they take Sarah Palin along with it!
richie

[africancoins]

This Guadeloupe 1 Franc 1903 has 20 sides.

You can about pick out the sides in the image.

Thanks Mr Paul Baker

[Galapagos]

1.  12 is quite a common choice for multi-sidedness ...  3 sides is quite rare for circulating coins (Cook Is $2), 4 has been done (various Indian denominations), 5 (Yemen), 6 (Egypt), 7 (Britain et al.), 8 (Egypt again, also Maltese 25c?), 9 (somewhere - can't think off-hand)...

Nine sides? The one you're thinking of is the Tuvalu one dollar coin, depicting a turtle, and first issued in 1976.

[BC Numismatics]

The Canadian Loonie,which has been in circulation since 1987 as a replacement for the Voyageur $1,is also a multi-sided coin as well.It has 11 sides.

Aidan.

[Figleaf]

Just guessing here, but maybe a number of sides (the number of sides is always equal to the number of corners) divisible by 3 is easier for modern machine tools, because the operator can simply set the corners as a whole number of degrees, e.g. 12 sides would translate into 15° corners, which are relatively easy to construct, even with paper and a compass.

Peter

[Figleaf]

As a compass user, have you still used logarithm tables and slide rules? It is amazing how much ballast knowledge you can gather in school.

Yes, I've found that "sides" expression puzzling. I am just not used to two-dimensional objects...

Peter

[tonyclayton]

As a compass user, have you still used logarithm tables and slide rules? It is amazing how much ballast knowledge you can gather in school.

Yes, I've found that "sides" expression puzzling. I am just not used to two-dimensional objects...

Peter

There are times when using a slide rule is quicker than using a calculator!  Furthermore, in most cases three significant figures is all you need.

[Figleaf]

My children grab a calculator for dividing 1024 by 2  . My daughter once got stuck in an exam, trying to figure out what 1/-1 would be equal to. They don't know what a slide rule looks like...

Peter