1. The problem statement, all variables and given/known data Let us assume that ray XY is a limiting parallel to line l, with P*X*Y. Prove that ray PY is a limiting parallel to line l. 2. Relevant equations Steps will go something like this: Show that ray PZ meets line lat a point V. Pick a point S such that P is between S and Z. Show that SX meets line PQ in a point U such that P is between U and Q. Choose any W such that X is between U and W and show that ray XW is between ray XY and ray XR so that ray XW meets line l at point T. 3. The attempt at a solution Since we know that ray XY is a limiting parallel ray, we can get that ray XW interests line l at the point T because it is between ray XY and ray XY. I'm not really sure where to go from here.