
It is given that (OR ⊥ PQ) and \(∠\)POQ = 180°

We can rewrite it as \(∠\)ROP = \(∠\)ROQ = 900
Since, \(∠\)ROP =\(∠\)ROQ
It can be written as
\(∠\)POS + \(∠\)ROS = \(∠\)ROQ
\(∠\)POS + \(∠\)ROS = \(∠\)QOS – \(∠\)ROS
\(∠\)SOR + \(∠\)ROS = \(∠\)QOS – \(∠\)POS
\(⇒\) 2\(∠\)ROS = \(∠\)QOS – \(∠\)POS
i.e, \(∠\)ROS = \(\frac{1}{2}\) (\(∠\)QOS – \(∠\)POS)



(i) The kind of person the doctor is (money, possessions)
(ii) The kind of person he wants to be (appearance, ambition)
ABCD is a quadrilateral in which AD = BC and ∠ DAB = ∠ CBA (see Fig. 7.17). Prove that
(i) ∆ ABD ≅ ∆ BAC
(ii) BD = AC
(iii) ∠ ABD = ∠ BAC.
