SOLUTION: number of diagonals from each vertex in a poligon of 8 sides?

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Question 102974: number of diagonals from each vertex in a poligon of 8 sides?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
Use this formulas
1. n – 3
and
2. %28n%28n-3%29%29%2F%282%29
to find number of non-intersecting (formula 1.) and intersecting (formula 2.) diagonals
if n+is the+number+of+vertexes
you have n+=+8

if you are counting non-intersecting diagonals, will be
%28n-3%29 diagonals
n –+3 = 5 non-intersecting diagonals
if you are counting intersecting diagonals,will be
%28n%28n-3%29%29%2F%282%29+
%288%288-3%29%29%2F%282%29+=+20 intersecting diagonals