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ABCD is a quadrilateral such that diagonal AC bisects the angles A and C. Prove that AB = AD and CB = CD. - Mathematics

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Question

ABCD is a quadrilateral such that diagonal AC bisects the angles A and C. Prove that AB = AD and CB = CD.

Sum

Solution

Given: In a quadrilateral ABCD, diagonal AC bisects the angles A and C.


To prove: AB = AD and CB = CD

Proof: In ΔADC and ΔABC,

∠DAC = ∠BAC  ...[∵ AC is the bisector of ∠A and ∠C]

∠DCA = ∠BCA  ...[∵ AC is the bisector of ∠A and ∠C]

And AC = AC   ...[Common side]

∴ ΔADC ≅ ΔABC   ...[By ASA congruence rule]

 AD = AB   ...[By CPCT]

And CD = CB  ...[By CPCT]

Hence proved.

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Chapter 7: Triangles - Exercise 7.4 [Page 71]

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NCERT Exemplar Mathematics [English] Class 9
Chapter 7 Triangles
Exercise 7.4 | Q 17. | Page 71

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