Medium.png
In a circle, chords \(AB\) and \(CD\) are equal and, when produced, intersect at \(R\). Verify that \(RB=RD\)
 
Explanation:
 
Now, Join \(OR\), draw \(OL⊥ AB\) and \(OM⊥ CD\).
 
Circle session 9 question 6 image 3.png
 
Here, \(AB = CD\). 
 
Therefore, \(OL = \)      []
 
In \(△OLR\) and \(△OMR\),
 
\(OL =\)
 
\(∠OLR=∠\) [] and
 
\(OR= \)\(OR\)       []
 
Therefore, \(△OLR≅△OMR\) [RHS congruence rule] 
 
Now, \(LR = \)\(MR\)       [by ]    .....(1)
 
Now, \(AB = CD\).
 
\(\frac{1}{2}AB=\frac{1}{2}CD\) 
 
\(BL=\)        .....(2) 
 
[]
 
On subtracting (2) from (1) , we get
 
\(LR − BL = MR − DM\)
 
Therefore, \(RB = RD\)
 
Hence, proved.