In Fig., \(OP = OQ\) and \(OS = OR\). Prove that
 
(i) \(∆ POS ≅ ∆ QOR\) and
 
(ii) \(PS || QR\)
 
AR3-tri - Copy (2).png
 
Proof:
 
(i) In \(∆ POS\) and \(∆ QOR\),
 
\(OP = OQ\) [Given]
 
\(OS = OR\) [Given]
 
\(\angle POS = \angle\) ( )
 
Thus, \(∆ POS ≅ ∆ QOR\) (by the congruence rule),
 
Hence proved
   
(ii)  In \(\triangle POS\) and \(\triangle QOR\), we have:
 
\(∠ OPS = ∠ OQR\) []
 
Therefore, \(PS \parallel  QR\).
 
Hence, we proved.