Solve this questions please fast Share with your friends Share 0 Varun Rawat answered this Dear Student, Let ABCD be a parallelogram. To show that ABCD is a rectangle, we have to prove that one of its interior angles is 90º. In ΔABC and ΔDCB, AB = DC (Opposite sides of a parallelogram are equal) BC = BC (Common) AC = DB (Given) ∴ ΔABC ≅ ΔDCB (By SSS Congruence rule) ⇒ ∠ABC = ∠DCB [CPCT] It is known that the sum of the measures of interior angles on the same side of transversal is 180º. ∠ABC + ∠DCB = 180º (AB || CD) ⇒ ∠ABC + ∠ABC = 180º ⇒ 2∠ABC = 180º ⇒ ∠ABC = 90º Since ABCD is a parallelogram and one of its interior angles is 90º, ABCD is a rectangle. Regards 0 View Full Answer Dishank Buddy answered this Please find your answer attached below :- Regards:) 1