Math Is Fun Forum

shoegazer

Member

Registered: 2010-05-10

Posts: 2

Angles of a Rhombic Dodecahedron?

Hello Math peeps ,

I'm constructing a Rhombic Dodecahedron and have searched online for a while to no avail for the answer to my questions.

What are the angles of a single face of the RD?  I thought it was 2 equilateral triangles fixed together which made the dimensions of one face, but after building I found out that it's really not.

Here's the shape just to be clear:
http://realwireless.files.wordpress.com/2008/06/240px-rhombicdodecahedron.jpg

and here's a website with lots of math on it yet doesn't include the angles of the RD faces (at least in a language I'm familiar with )

http://www.kjmaclean.com/Geometry/rhombicdodeca.html

Thanks,

Daniel

Sunnym

Guest

Re: Angles of a Rhombic Dodecahedron?

I don't know the angles myself, but I did a search for rhombi dodecahedron pattern, here is one of the instructions;
http://britton.disted.camosun.bc.ca/stellated_rhombic_dodecahedron.pdf

shoegazer

Member

Registered: 2010-05-10

Posts: 2

Re: Angles of a Rhombic Dodecahedron?

Thanks Sunnym.  It wasn't what I was looking for but I appreciate the reply.

Otherwise... I don't see much point of this forum if you can't get math help on it.  Maybe I don't see the forum right.  Was my question not a math question?

I realized that the answer is here:
http://mathworld.wolfram.com/RhombicDodecahedron.html
I just couldn't read the symbols.  There are two angles.
one is roughly 70.53 degrees and the other is roughly 109.47 degrees

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Angles of a Rhombic Dodecahedron?

Hi Daniel;

Otherwise... I don't see much point of this forum if you can't get math help on it.  Maybe I don't see the forum right.  Was my question not a math question?

It can be a litte discouraging when you don't get an answer to a question but you have to remember the people on the forum are not machines. Many questions, worthwhile questions, get overlooked on all forums. Here are some reasons.

1) The question is too specialized, meaning it is your specialty and few others no anything about it.

2) The question is not specific enough to get an answer. Saying I don't know the symbols is one of those. What specifically don't you understand? Like enrolling in French class and saying to the teacher, I don't know french.

3) The question is too tough for the people on the forum. No one knows everything, quite the contrary.

4) You have to do your own research first. Like googling and finding pdf's and such. This is is an important step in conditioning your mind to ask for and receive help.

Your problem was not ignored, I looked at it as I do all problems. I am sure others did too. I didn't have anything useful to say. For that I am sorry. I feel the forum is really good thing and hope you will not get down on it because one question was not answered.

We all see the forum differently as we see the world differently. Hopefully, I will be of more assistance next time.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

KrazyKyngeKorny

Member

Registered: 2010-06-07

Posts: 12

Re: Angles of a Rhombic Dodecahedron?

Thanks Sunnym.  It wasn't what I was looking for but I appreciate the reply.

I realized that the answer is here:
http://mathworld.wolfram.com/RhombicDodecahedron.html
I just couldn't read the symbols.  There are two angles.
one is roughly 70.53 degrees and the other is roughly 109.47 degrees

Be sure your calculator is in degree mode. Punch in 1/3=
[2nd] cos

for a (alpha)

2 √
[2nd]tan
x2=
-180=
[+/-]

for the second angle.

The lines below x2 are to re-reference the angle from 180 degrees.