Given ABCD is a parallelogram and AE = CF
To show OE = OF
Construction Join BD, meet AC at point O.
Proof Since, diagonals of a parallelogram bisect each other.∴OA=OC
And OD = OB
Now, OA = OC
And AE = CF [given]
⇒OA−AE=OC−CF
⇒OE=OF
Thus, BFDE is a quadrilateral whose diagonals bisect each other.
Hence, BFDE is a parallelogram. [Hence proved]