(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Prove that for a simple, connected, planar graph, 3f ≤ 2e where f = faces and e = edges

3. The attempt at a solution

My professor went over this in class, and mentioned something about "double counting," which I do not really understand. I tried saying that it takes 2 counts to define an edge and 3 to define a face, but from here I am not sure what to do as I am unfamiliar with double-counting proofs.

Thanks for the help.

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# Homework Help: Graph planarity

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