This pseudoline arrangement is a uniform variation of Ceva's theorem, which has an easy to prove slope constraint (as a line arrangement, with line 0 projected to infinity). Carroll, [2000d] shows:
sin(θF-θE)sin(θD-θC)sin(θB-θA) < sin(θF-θA)sin(θE-θD)sin(θC-θB)
A
0< A< C< D< F< E
