Geodesic dome triangles

[205alive]

I'm constructing a geodesic dome from cardboard. The first of the two triangles I'm using is equilateral with a side length of 345mm and height of 300mm. The second should be isocelean (sic?), with one side being the same 345mm - but what should the remaining side lengths be?

Can anyone give me the easiest formula to determine the unknown side lengths, please?

[205alive]

Perpendicular height.

[205alive]

Devil2575 said:

Does the size of the second triangle not depend on how big you wish to make the dome?

Er...pass!

[205alive]

Devil2575 said:

http://science.howstuffworks.com/engineering/struc...

According to this link you only need one one size of equilateral triangle.

So it does, paragraph six line two - thanks for that, been a bit confused - I found a good geodesic model for google sketchup, but the two triangles used in the model definitely have different areas, according to the face/component/etc info you can bring up.

Will find out tomorrow when I set about my cardboard triangles.

[205alive]

Just to update, it hasn't really worked out so far and, despite the ray of false hope offered yesterday, looks like common geodesic wisdom is suggesting it won't happen.

I did get an icosahedron out of it, as well as various more useless structures. Will have another crack tomorrow just in case there is the possibility of even knocking a third of a sphere up, as I would consider that a small but exciting success, given the current status of my life/empty void.

[205alive]

In view of the results, steohedron is more appropriate (rhymes with 'light'). Never mind.