So OA = oc be Σ df
And because the straight line EF passes through AC to O.
So ∠AOE =∠ Buddha
And because BE∑DF
So ∠OEA=∠OFC
Because OA=OC ∠AOE=∠FOC ∠OEA=∠OFC(AAS)
So △OAE is equal to △OCF.
So OE=OF