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NDA2011MathematicsThree Dimensional GeometryActual

What is the angle between the lines whose direction cosines are proportional to (2,3,4) and (1,-2,1) respectively?

Options

  1. A90^
  2. B60^
  3. C45^
  4. D30^

Correct answer

A. 90^

Step-by-step solution

The correct answer is option (A).

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