Manipal MET2012MathematicsSequences and Series
In a triangle, the angle are in AP and the lengths of the two larger sides are 10 and 9 , respectively, then the length of the third side can be
Options
- A5 6
- B0.7
- C15- 6
- DNone of these
Correct answer
A. 5 6
Step-by-step solution
Let the angles be A=x-d, B=x, C=x+d , Then, x-d+x+x+d=180^ 3 x=180^ x=60^ Therefore, two larger angles are B and C . Hence, b=9 and c=10 . Now, array cc & B= c^2+a^2-b^2 2 a c & 1 2 = 100+a^2-81 20 a & a^2-10 a+19=0 & a=5 6 array