AP EAMCET · Maths · Properties of Triangles
In , if , then
- A
- B
- C
- D
Answer & Solution
Correct Answer
(C)
Step-by-step Solution
Detailed explanation
The ratio is given as, a:b:c=3:5:7. Considera=3x, b=5x, c=7x. Now, cosA+cosB=b2+c2-a22bc+a2+c2-b22ac =(5x)2+(7x)2-(3x)22(5x)(7x)+(3x)2+(7x)2-(5x)22(3x)(7x) =65x270x2+33x242x2 =6570+3342 =127
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