MHT CET202615 April 2026Evening ShiftMathematicsVector AlgebraActual

If a + b + c = 0 , | a | = | b | = | c | = 3 and is the angle between b and c then ^2 + ^2 =

Options

A2 3
B5 3
C8 3
D10 3

Correct answer

D. 10 3

Step-by-step solution

Given a + b + c = 0 b + c = - a Squaring both sides, we get | b |^2 + | c |^2 + 2 b c = | a |^2 Substituting | a | = | b | = | c | = 3 , 3^2 + 3^2 + 2| b || c | = 3^2 9 + 9 + 2(3)(3) = 9 18 + 18 = 9 18 = -9 = - 1 2 This gives = 120^ Now, ^2 + ^2 = ^2(120^ ) + ^2(120^ ) = (- 3 )^2 + (- 1 3 )^2 = 3 + 1 3 = 10 3 Answer: 10 3

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