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AP EAMCET20224 Jul 2022Evening ShiftMathematicsProperties of TrianglesActual

If a = 2 , b = 3 , c = 4 in a triangle A B C , then cos C =

Options

  1. A1 4
  2. B- 1 4
  3. C1 2
  4. D- 1 2

Correct answer

B. - 1 4

Step-by-step solution

Given: a = 2 ,   b = 3 ,   c = 4 Now, cos C = a 2 + b 2 - c 2 2 a b ⇒ cos C = 4 + 9 - 16 2 × 2 × 3 ⇒ cos C = - 3 2 × 2 × 3 ⇒ cos C = - 1 4

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