Four points W, X , Y, Z are chosen at random on the circumference of a circle. What is the probability that the segments WX and YZ intersect?
Don't know how to approach? I suspect finding the probability of cases where they don't intersect and then subtractiing from 1 would be easier?
Here is an earier solution to this question by CPhill
https://web2.0calc.com/questions/four-points-j-k-l-and-m-are-chosen-at-random-on-the