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MHT CET202210 Aug 2022Morning ShiftMathematicsProperties of TrianglesActual

In a triangle A B C , with usual notations, if b= 3 , c=1, A=30^ , then angle B is

Options

  1. A60^
  2. B90^
  3. C30^
  4. D120^

Correct answer

D. 120^

Step-by-step solution

aligned & A= b^2+c^2-a^2 2 b c & 30^ = 3+1-a^2 2 3 1 & 3 2 = 4-a^2 2 3 & a=1 aligned Now B= c^2+a^2-b^2 2 c a = 1^2+1^2-( 3 )^2 2 1 1 =- 1 2 B=120^

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