There are 10 possible diagonals drawn from one vertex of the 13-gon which divide it into 11 nonoverlapping triangles.
There are: 0.5*(302-(3*30)) = 405 diagonals
1/2*15*(15-3) = 90 diagonals.
104 16x ((16-3)/2) =104
22-gon
252 diagonals
There are 119 diagonals.
It has 495 diagonals.
It has 54 diagonals
170
78
There are 10 possible diagonals drawn from one vertex of the 13-gon which divide it into 11 nonoverlapping triangles.
0.5*(152-45) = 90 diagonals
A 20 sided polygon has 170 diagonals
There are 275 diagonals in a 25 sided polygon
39*36/2 = 702 diagonals.
many triangles does a regular 46-gon have