4. On one of the sides of a triangle, 60 points are taken, and on another - 50. (These points are distinct from the vertices of the triangle.) Each vertex at the base is connected by straight line segments to the points taken on the opposite side. How many intersection points of these segments are formed in this case?
4. Each of the 60 segments drawn from one vertex intersects each of the 50 segments drawn from another vertex, so we get 3000 such points $(50 \cdot 60=$ $=3000)$.