Given:

AB ∥ CD , BC ∥ AD , BD ∩ AC = O, M∈BC ; N∈AD
Prove: BM = ND

BD and AC are diagonals
MN goes through the center which is also where BD and AC bisect and point O

Can U Guys Put the Answer it would be a BIG HELP, Thanks (:

2 answers

it is easy to show that

∆NOD ≅ ∆MOB

check out vertical angles and recall that the diagonals bisect each other.
Gurp