Your question is not that well defined.  For example, suppose we want to convert a hexagon (a six sided polygon) to a triangle.  We can choose any three of the sixvertices to make a triangle.  There would be 6C3 ways of doing this.  I would put the coords of the poly as a list: L:=[[x1, y1],[x2,y2],...]    You could then make n lengths, being the sides of the n-gon, using the formula length:=sqrt((x[i]-x[i-1]^2+(y[i]-y[i-1])^2):   Choose three of these and you have a triangle...

....well maybe not!  You would have to check that this is possible ie does the triangle inequality hold?    So 6C3 is the maximum number of triangles that could be constructed.

   Hope this helps. .