Pls answer these questions. Share with your friends Share 0 Global Expert answered this In the IIgm ABCD:AO=OC......(i) (diagonals of a parallelogram bisect each other)AE=CF.......(ii) (given)Subtracting (ii) from (i):AO-AE=OC-CFEO=OF......... (iii)In ∆DOE and ∆BOF:EO=OF (proved above)DO=OB (diagonals of a parallelogram bisect each other)∠DOE =∠BOF (vertically opposite angles)By SAS congruence: ∆DOE≅ ∆BOF∴ DE=BF (c.p.c.t)In ∆BOE and ∆DOF:EO=OF (proved above)DO=OB (diagonals of a parallelogram bisect each other)∠DOF =∠BOE (vertically opposite angles)By SAS congruence: ∆DOE≅ ∆BOF∴ DF=BE (c.p.c.t)Hence, the pair of opposite sides are equal. Thus, DEBF is a parallelogram. 6 View Full Answer