# Hi, noob looking for help symmetryWatch

#1
Hi, just joined the forum. I'm having problems trying to find all twelve of the symmetries for a triangular prism

The triangles are equilateral and the rectangles are identical to each other.

I have found 6 rotational and 4 reflective but I have spent nearly all day trying to find the other two but have had no joy.

Can anyone guide me through this please?
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5 years ago
#2
(Original post by jojo55)
Hi, just joined the forum. I'm having problems trying to find all twelve of the symmetries for a triangular prism

The triangles are equilateral and the rectangles are identical to each other.

I have found 6 rotational and 4 reflective but I have spent nearly all day trying to find the other two but have had no joy.

Can anyone guide me through this please?
If you've found six rotational symmetries and a reflective symmetry, then the remaining symmetries of the object will be given by doing the reflective symmetry followed by one of the rotations.
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5 years ago
#3
Two lines at 90 degrees to each other on each rectangle side (cutting in towards the point of the triangle), and three lines per triangle side (cutting in to the other triangle side). That makes 2*3 + 3*2 = 12 lines of symmetry.
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#4
(Original post by Mark13)
If you've found six rotational symmetries and a reflective symmetry, then the remaining symmetries of the object will be given by doing the reflective symmetry followed by one of the rotations.

Thanks for the quick responses. I understand it now
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5 years ago
#5
(Original post by jojo55)
Thanks for the quick responses. I understand it now
Are you doing the same course as this person:

http://www.thestudentroom.co.uk/show....php?t=2300544

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#6
(Original post by davros)

Are you doing the same course as this person:

http://www.thestudentroom.co.uk/show....php?t=2300544

No, I only needed to find out the symmetries, not even sure what a conjugacy class is.
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