



 
Hi Sofia, If you go to the Quandaries and Queries page on Math Central Julie's asked about the number of diagonals from one vertex of a 12 sided polygon. In Leeanna's response she defines a diagonal and answers Julie's question. Karan asked about the number of diagonals in an 11 sided polygon (a hendecagon) and Penny leads Karan in a process to build on Leeanne's response above to answer her question. Edna's question is about the number of diagonals in an $n$ sides polygon and Stephen takes an entirely different approach to answer her question. If you want to extend Leeanne's and Penny's approach to a general formula you might want to look at our reply to Steven. Let me know if you need any other assistance,  


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