Any n-sided convex polygon with more than 3 sides will have n(n-3)/2 diagonals. For instance, let us look at a square. A square has 4 sides and 2 diagonals. Let us apply this formula with n = 4. We get 4(4-3)/2 = 2 diagonals. Here is a question on finding the number of diagonals. If a n-sided convex polygon has 14 diagonals, how many sides does the polygon … [Read more...] about Number of diagonals in convex polygon : GMAT