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


Theorem 8.7 If the diagonals of a quadrilateral bisect each other, then it is a parallelogram. Given: ABCD is a quadrilateral with AC and BD are diagonals intersecting at O Diagonals bisect each other i.e. OA = OC & OB = OD To Prove: ABCD is a parallelogram Proof : In AOD and COB OA = OC AOD = COB OD = OB AOD COB ODA OBC OAD = OCB Similarly, we can prove AOB COD ABO = CDO Thus, In ABCD, Both pairs of opposite sides are parallel, ABCD is a parallelogram

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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.