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MHT CET202015 Oct 2020Evening ShiftMathematicsVector AlgebraActual

The perimeter of the triangle whose vertices have the position vectos + + k , 5 +3 -3 k and 2 +5 +9 k is

Options

  1. A( 15 - 157 ) units
  2. B(15+ 157 ) units
  3. C(15- 157 ) units
  4. D( 15 + 157 ) units

Correct answer

B. (15+ 157 ) units

Step-by-step solution

Let a = i + j + k , b =5 i +3 j -3 k , c =2 i +5 j +9 k AB =4 i +2 j -4 k AB = 16+4+16 =6 BC =-3 i +2 j +12 k | BC |= 9+4+144 = 157 AC = i +4 j +8 k AC = 1+16+64 =9 Perimeter =| AB |+| BC |+| AC |=15+ 157

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