A) \[b\]
B) \[2b\]
C) \[3b\]
D) \[4b\]
Correct Answer: B
Solution :
Since,\[\frac{A}{2}+\frac{B}{2}=\frac{\pi }{2}-\frac{C}{2}\] \[\Rightarrow \]\[\frac{\tan \frac{A}{2}+\tan \frac{B}{2}}{1-\tan \frac{A}{2}\tan \frac{B}{2}}=\tan \left( \frac{\pi }{2}-\frac{C}{2} \right)\] \[\Rightarrow \]\[\frac{\frac{5}{6}+\frac{20}{37}}{1-\frac{5}{6}\times \frac{20}{37}}=\cot \frac{C}{2}\] \[\Rightarrow \]\[\frac{305}{122}=\cot \frac{C}{2}\] \[\Rightarrow \]\[\tan \frac{C}{2}=\frac{2}{5}\] Now, \[\tan \frac{A}{2}\tan \frac{C}{2}=\frac{5}{6}\times \frac{2}{5}\] \[\Rightarrow \]\[\sqrt{\frac{(s-b)(s-c)}{s(s-a)}}\sqrt{\frac{(s-a)(s-b)}{s(s-c)}}=\frac{1}{3}\] \[\Rightarrow \] \[\frac{s-b}{s}=\frac{1}{3}\] \[\Rightarrow \] \[3s-3b=s\] \[\Rightarrow \] \[2s=3b\Rightarrow a+b+c=3b\] \[\Rightarrow \] \[a+c=2b\]You need to login to perform this action.
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