### Brain Teasers

# Dimension

Series
Series teasers are where you try to complete the sequence of a series of letters, numbers or objects.

1,1,infinity,5,6,?

What is the next number?

What is the next number?

### Hint

The title gives the clue.### Answer

3.In 0-D, there is a dot. Nothing else. So, there is one.

In 1-D, the line, is the only one.

In 2-D there are infinity regular polygons

In 3-D, 5 Platonic Solids appear:

tetrahedron, cube, octahedron, dodecahedron, and icosahedron.

In 4-D, 6 regular polytopes show:

5-cell, 8-cell, 12-cell, 24-cell, 120-cell, and 600-cell.

In the fifth dimension, only the simplex, hypercube, and cross polytope are regular.

This leaves us with 3 as our answer.

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## Comments

Fascinating.

Very tough!

"infinity" is not a number, but I'll let you slide.

I don't get it.

What was that again. In 4-d bubonic poles from Finland appear?

that is tough!!!!!!!

dont get it.. too confusing 4 me!

Whoa! That was a cool one!

Beautiful. I did not realize that there are only a few regular forms in higher dimensions, but that does make sense. Makes you think. I usually think of the dimensions as being so relative and increasing exponentially in every way, but that's really fascinating that the 3rd is the only one (as far as we've discussed, that is) with an infinite number of regular forms.

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