Why can't a (5,5,4) solid exist?

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SUMMARY

The discussion centers on the impossibility of a solid with a vertex configuration of (5,5,4). The key argument is based on the geometric principle that a p-gon must be surrounded by alternating q-gons and r-gons, as stated in the Wikipedia article on vertex configurations. Specifically, for a uniform (5,5,4) solid, the arrangement leads to two squares or two pentagons abutting each other, violating the required alternating structure. This contradiction confirms that such a solid cannot exist.

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So i was reading my geometry textbook and it said "and obviously there can be no solid where every vertex has a (5,5,4) arrangement"; unfortunately, this is not an obvious fact to me. Can somebody explain to me what makes this so obvious? This statement was the end of a proof by contradiction so i feel I should really understand why it's true.
 
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This statement from the wikipedia article sums it up:

Specifically p.q.r implies that a p-gon is surrounded by alternating a q-gons and r-gons, so either p is even orq equals r.

If something is uniform 5.5.4 then focus on a pentagon. Each edge alternates being a pentagon or a square, but when you go all the way around the pentagon you will get two squares (or two pentagons) abutting each other.
 

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