A polygon with n sides has n*(n-3)/2 diagonals. Simple as that. So a 9 sided polygon has 9*6/2 = 27 diagonals.
For a 9 sided polygon it is: 0.5*(92-(3*9)) = 27 diagonals
The formula for the number of diagonals that an N-sided polygon has is# diagonals = N(N-3)/2N(N-3)/29(N-3)/29*(9-3)/29*6/2 = 54/227
A six sided hexagon has nine diagonals.
7
A polygon with n sides has n*(n-3)/2 diagonals. Simple as that. So a 9 sided polygon has 9*6/2 = 27 diagonals.
A 4-sided polygon has 2 diagonals. A 5-sided polygon, 5. 6-sided, 9. By induction, an n-sided polygon has 'n*(n-3)/2' diagonals. "n" is how many sides a shape has. so, (7)*(7-3)/2 now we have, 7*4/2 so, 28/2 = 14 Therefore, a 7-sided polygon would have 14 diagonals.
A regular octadecagon (an eighteen sided polygon) would have nine diagonals.
The formula is: 0.5*(n2-3n) where n is the number of sides of the polygon. So: 0.5*(81-27) = 27 diagonals
For a 9 sided polygon it is: 0.5*(92-(3*9)) = 27 diagonals
Plug 9 as n in this formula: n(n-3)/2
The formula for the number of diagonals that an N-sided polygon has is# diagonals = N(N-3)/2N(N-3)/29(N-3)/29*(9-3)/29*6/2 = 54/227
8+7+6+5+4+3+2+1 = 36 diagonals
A six sided hexagon has nine diagonals.
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