Q9 of 16 Page 133

In the given figure ABCD is quadrilateral in which AB is parallel to DC and AD is parallel to BC. Prove that: ∠ADC = ∠ABC.

Given: ABCD is a quadrilateral.


AB ∥ DC and AD ∥ BC.



To Prove: ∠ADC = ∠ABC


Proof:


As given, AB ∥ DC


& AD ∥ BC


⇒ ABCD is a parallelogram.


By property of parallelogram, we can say


Opposite angles are congruent in a parallelogram.


⇒ ∠ABC = ∠ADC


Hence, proved.


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