AP EAMCET202022 Sep 2020Evening ShiftMathematicsSequences and SeriesActual
The angles A, B, C of a triangle A B C are in AP. If A B=6, B C=7 , then A C=
Options
- A40
- B41
- C43
- D6
Correct answer
C. 43
Step-by-step solution
aligned & (c) Given In A B C , & A, B, C are in AP & & In A B C, aligned aligned A+ B+ C & =180^ 2 B+ B & =180^ B & =60^ aligned From cosine rule, aligned B & = A B^2+B C^2-A C^2 2 A B B C 60^ & = 36+49-x^2 2 6 7 1 2 & = 85-x^2 84 41 & =85-x^2 aligned aligned x^2 & =85-42 x^2 & =43 x & = 43 aligned Hence, option (3) is correct.