A) \[5\pm \sqrt{6}\]
B) \[0.7\]
C) \[15-\sqrt{6}\]
D) None of these
Correct Answer: A
Solution :
Let the angles\[A=x-d,\,\,B=x,\,\,C=x+d,\] Then,\[x-d+x+x+d={{180}^{o}}\] \[\Rightarrow \] \[3x={{180}^{o}}\] \[\Rightarrow \] \[x={{60}^{o}}\] Therefore, two larger angles are\[B\]and\[C\]. Hence,\[b=9\]and\[c=10\]. Now, \[\cos B=\frac{{{c}^{2}}+{{a}^{2}}-{{b}^{2}}}{2ac}\] \[\Rightarrow \] \[\frac{1}{2}=\frac{100+{{a}^{2}}-81}{20a}\] \[\Rightarrow \] \[{{a}^{2}}-10a+19=0\] \[\Rightarrow \] \[a=5\pm \sqrt{6}\]
You need to login to perform this action.
You will be redirected in
3 sec
