AP EAMCET · Maths · Properties of Triangles
In \(\triangle A B C\), if \(a: b: c=4: 5: 6\), then \(\frac{\cos A+3 \cos C}{\cos B}=\)
- A \(1\)
- B \(4\)
- C \(2\)
- D \(3\)
Answer & Solution
Correct Answer
(C) \(2\)
Step-by-step Solution
Detailed explanation
\(\cos A = \frac{b^2+c^2-a^2}{2bc} = \frac{(5k)^2+(6k)^2-(4k)^2}{2(5k)(6k)} = \frac{25+36-16}{60} = \frac{45}{60} = \frac{3}{4}\) \(\cos B = \frac{a^2+c^2-b^2}{2ac} = \frac{(4k)^2+(6k)^2-(5k)^2}{2(4k)(6k)} = \frac{16+36-25}{48} = \frac{27}{48} = \frac{9}{16}\)…
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