A) 4
B) 2
C) 0
D) \[-2\]
Correct Answer: B
Solution :
:\[\overrightarrow{A}\,\overrightarrow{B}=0\]if\[\overrightarrow{A}\]and\[\overrightarrow{B}\]are perpendicular to each other. \[\therefore \] \[(4\hat{i}+5\hat{j}+r\hat{k}).(2\hat{i}-4\hat{j}+6\hat{k})=0\] \[\therefore \] \[8-20+6r=0\] or \[6r=12\] or \[r=2\]You need to login to perform this action.
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