hi jesseherring

Check this page

http://en.wikipedia.org/wiki/Icosidodecahedron

Is that what you want?

This page gives the co-ordinates of the vertices.  So a bit of 3-D vector geometry should give the angles.

Post back to confirm the solid and that'll give me time to work out a suitable vector equation.  (It's kinda late here in the UK so I need to sleep on it. 

Bob

Last edited by bob bundy (2011-07-28 08:11:37)

Hi;

Instead of dealing with the whole problem at once why not just post where you are right now? What particular calculation is giving you trouble. What have you got so far?

you should just figure out what the angles are in a regular pentagon and a equilateral triangle.

Last edited by anonimnystefy (2011-07-29 01:17:26)

maybe and maybe not.

as i can see on the picture the icosidodecahedron consists of pentagons and triangles.

Last edited by anonimnystefy (2011-07-29 01:22:51)

Hi jesseherring;

I remember this question, I also remember no one resolved it.

It looks very complicated.

bobby

     i could not find any threads that were on this topic.  maybe i was searching using the wrong keywords? 

     anonimnystefy,  i do not think its the same thing

to be able to safely cut all the pieces i would say 14-18 inches

wondering if anyone could explain these diagrams to me.  if i understand how these work i believe that i may be able to eventually figure out the needed angles for the icosidodecahedron.

jesse

Uploaded Images

What I meant that from post #16 you could actually build one out of stiff cardboard or say sheet metal. They are providing the template. We used to construct fairly large and perfect pyramids with the same idea.

thats my next step i guess is to build a model using a template.

Sometimes calculating is out and you are left with measurements. In the old days Galileo and Kepler solved tough math problems by weighing things. They were actually able to determine centers of gravity and areas under curves.

That page has printed out for a template that I downloaded. Take that template and blow it up with a good printer.

find angles for a 3V form of the icosahedron

An icosahedron is not the same shape. What is learned by doing that may not carry over to the real problem.

Maybe! If I can not someone else can. First I would construct a model, either in reality or in a computer. A 3D model, those 2D drawings do not provide me with enough insight.

Your first post says you want to build it. Can you really measure out an angle of 7 degrees 11 minutes and 31 seconds? If you know the angles what good does that do towards building it? I mean do you really require the precision that calculation gives to construct it? You will have to approximate those angles in your construction.

So the question is are you building it or mathematically describing it?

Hi;

Let me know how you do. If you decide to make it our of stiff cardboard we used to half score ( cut through ) the line with an exacto knife. That allows the edges to bend but still stay together. This makes a somewhat stronger figure than paper.