18 triangles
Three triangles
5 triangles are formed.
Either 12,14,16,or18 I think 18. * * * * * The correct answers is 4. You can draw only 3 diagonals from one vertex.
98
18
There are 7 triangles in a nonegon
7
A nine sided shape has 7 triangles
9-2 = 7 triangles
7
10080
7
4.
to calculate the number of possible triangles within a nonagon, one must use combinatorics. Understand that at first you have to pick the first vertex from 9 points, then the second from eight other possible points, and the third from 7 possible points. And finally that by this process any three vertices could be picked in 6 different orders. triangles possible are: 9*8*7/6 = 84 possible triangles in a nonagon
7
Five of them