1. Chapter 8 Class 9 Quadrilaterals
  2. Serial order wise


Theorem 8.8 A quadrilateral is a parallelogram if a pair of opposite sides is equal and parallel. Given : ABCD is a quadrilateral where AB CD & AB = CD To Prove : ABCD is a Parallelogram Proof : Given AB CD with transversal AC. BAC = DCA In ADC & CBA AB = CD BAC = DCA AC = CA ADC CBA Hence, DA = BC Thus, In ABCD, Both pairs of opposite sides are equal ABCD is a Parallelogram. Hence proved

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.