 
       
      
    Need solution for RD Sharma maths class 12 chapter 23 Scaler and Dot Product exercise Multiple choice question 15
Answer:
Option (c) 14
Hint:
If  are perpendicular, then 
Given:
  are perpendicular.
Solution:
Let 
If  are perpendicular, then 
Hence option (c) is correct
 
                 
                