∵ Quadrilateral ABCD is a parallelogram
∴ AB // CD
∴∠eao =∞∠fco (two straight lines are parallel and the internal dislocation angles are equal)
And ∵ AC is the diagonal of the parallelogram ABCD.
∴ O = Company
∠AOE = ∠COF (equal to vertex angle)
∴ △AOE = △COF (corner kick ASA)
∴ AE = CF
(2) If it is still in the parallelogram ABCD, the conclusion is the same.
In fact, as long as it is AB // CD and point O is the midpoint of AC, the conclusion is still the same, AE = CF