∵AH∥BC,∴AF:FD=AH:DC。

∵af:fd= 1:3,∴ah:dc= 1:3

And ∵AD is the midline on the side of BC, that is, d is the midpoint of BC.

∴BC=2BD=2DC,∴AH:BC= 1:6.

And ∵AH∨BC, so AE: EB = ah: BC = 1: 6.