The five sided Polygon has 5 diagonals
209
It is: 0.5*(144-36) = 54 diagonals
The formula is: 0.5*(n2-3n) = diagonals whereas n is the number of sides of the polygon
65
A 7 sided polygon has 14 diagonals
Number of diagonals = 1/2*(n2-3n) where n = the number of sides of the polygon.
It has 20 diagonals
The five sided Polygon has 5 diagonals
38 diagonals
number of diagonals = n(n-3)/2 n - number of sides of the polygon
Number of sides - 2
1/2*(n2-3n) = 665 diagonals where n means number of sides
11
209
It is: 0.5*(144-36) = 54 diagonals
The formula is: 0.5*(n2-3n) = number of diagonals when n is the number of sides of the polygon