AP EAMCET · Maths · Properties of Triangles
The sides of a \(\triangle A B C\) are given by \(a=3, b=5\) and \(c=3\). Then, \(\cos A=\)
- A \(2 / 6\)
- B \(1 / 6\)
- C 2/3
- D \(5 / 6\)
Answer & Solution
Correct Answer
(D) \(5 / 6\)
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & a=3, b=5, c=3 \\ & \cos A=\frac{b^2+c^2-a^2}{2 b c}\end{aligned}\) \(\begin{aligned} & =\frac{25+9-9}{2 \times 5 \times 3} \\ & =\frac{25}{30}=\frac{5}{6}\end{aligned}\)
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