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\(ABCD\) is a parallelogram and \(AP\) and \(CQ\) are perpendiculars from vertices \(A\) and \(C\) on diagonal \(BD\). Show that   (i) \(∆APB ≅ ∆CQD\) and   (ii) \(AP = CQ\)
 
Proof:
 
\(ABCD\) is a parallelogram

(i) In \(∆APB\) and \(∆CQD\), we have
 
\(∠APB = ∠CQD=\)\(^{\circ}\)
 
\(AB = CD\) [Opposite sides of the parallelogram are ]
 
As \(AB || CD\) and \(BD\) is a transversal, \(∠ABP = ∠CDQ\) [Alternate angles are equal]
 
Hence, \(∆APB  ≅  ∆CQD\) [By ]
 
(ii) As, \(∆APB ≅ ∆CQD\)
 
\(AP = CQ\) [By ]
 
Hence, proved.