D24. Sliding Ratios

Contributed by Yagub Aliyev, ADA University, Azerbaijan

Figure 4: Pivoting segment F H about G to cut B E and C D into two pieces each.

As shown in Figure 4, A B C is a triangle. Points F and E lie on side A B , with F closer to B . Point D lies on side A C . Point G is the intersection of segments B D and C E , and H is the intersection of ray F G with side A C . Prove that it must always be the case in this situation that

B F F E > D H H C ,

where in this inequality, B F (for example) denotes the length of the corresponding segment.

This problem originally appeared in the Prisoner’s Dilemma in the 2024 Fall issue of the PMP Newsletter. Solutions will be accepted through 2025 Jul 15.