How many distinct triangles can be formed by selecting three vertices of a regular octagon? (Triangles with different vertices are considered distinct even if they are congruent.)
EDIT
Like the guest says 8C3 = 56 !!!
But he/she says "by selecting 3 vertices of a regular octagon". So, shouldn't the number of distinct triangles be:
8C3 = 56 ???
+239 
