ABCD is a quadrilateral in which AD = BC and DAB = CBA (see Fig. 7.17). Prove that

(i) Δ ABD Δ BAC


(ii) BD = AC


(iii) ABD = BAC.


It is given in the question that:

AD = BC and


DAB = CBA


(i) In


AB = BA (Common)


DAB = CBA (Given)


AD = BC (Given)


Therefore,


By SAS congruence,



(ii) Since,



Therefore,


BD = AC (By c.p.c.t)


(iii) Since,



Therefore,


ABD = BAC (By c.p.c.t)


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