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AP EAMCET20228 Jul 2022Morning ShiftMathematicsProperties of TrianglesActual

In a ABC , if a =13, ~b =14 and c =15 , then

Options

  1. A1 5
  2. B1 7
  3. C3 4
  4. D4 5

Correct answer

A. 1 5

Step-by-step solution

WSA =1-2 Sin ^2 ( A 2 ) aligned & 2 Sin ^2 ( A 2 )=- WSA +1 & Sin ^2 ( A 2 )= -W S A+1 2 aligned Now WSA = b^2+c^2-a^2 2 b c = (14)^2+(15)^2-(13)^2 2 14 15 = 196+225-169 2 14 15 WSA = 196+225-169 2 14 15 = 3 5 aligned & Now Sin ^2 ( A 2 ) & Sin 2 ( A 2 )= - A+1 2 = ( 3 5 +1 2 )= 2 5 2 aligned

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