18. If in a convex decagon no three diagonals intersect at the same point inside the decagon, how many segments can the diagonals be divided into by their intersection points inside the decagon?
18. The number of diagonals equals $C_{10}^{2}-10=35$. Among these diagonals, there are a total of $C_{10}^{4}=210$ intersection points. Since each intersection point lies on two diagonals, the total number of line segments distributed among these diagonals is $35+2 \times 210=455$.