AP EAMCET202022 Sep 2020Morning ShiftMathematicsProperties of TrianglesActual
A B C , if a, b, c are its sides and C=60^ , find the value of a b+c + b c+a
Options
- A1
- B0
- C3 2
- D1 2
Correct answer
A. 1
Step-by-step solution
In a A B C , it is given C=60^ , then aligned & 60^ = a^2+b^2-c^2 2 a b & a b=a^2+b^2-c^2 c^2=a^2+b^2-a b aligned Now, a b+c + b c+a = a c+a^2+b^2+b c b c+a b+c^2+a c aligned & = a c+c^2+a b+b c a c+a b+c^2+b c a^2+b^2=c^2+a b & =1 aligned