Rotational Symmetry

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Hera
Posts: 856
Joined: Mon Feb 22, 2010 3:50 pm

Rotational Symmetry

Post by Hera »

I can't find a definitive answer on the following. If a shape, for example and an isosceles triangle, can only rotate into itself once in 360 degrees, would this be classed as having rotational symmetry of 1 or 0? I have always understood this to be 0 as if it can only rotate once this is not rotational symmetry but DS insists it is 1.

Any feedback greatly appreciated. Thanks.
Guest55
Posts: 16254
Joined: Mon Feb 12, 2007 2:21 pm

Re: Rotational Symmetry

Post by Guest55 »

This is a really good question!

Some books say 'rotational symmetry of order 1' and others say no rotational symmetry.
Hera
Posts: 856
Joined: Mon Feb 22, 2010 3:50 pm

Re: Rotational Symmetry

Post by Hera »

Interesting; maybe it is safer then to record it as one as it shows that the child understands that it can only go into itself once. Thanks.
Proud_Dad
Posts: 500
Joined: Fri Oct 11, 2013 9:55 am

Re: Rotational Symmetry

Post by Proud_Dad »

According to wikepdia it looks as thought the answer is 1.

http://en.wikipedia.org/wiki/Rotational_symmetry" onclick="window.open(this.href);return false;

Although personally I find this a bit meaningless because that means that ANY random non-symmetrical object or shape has a rotational symmetry of 1.

But I guess that's just the way its defined.
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