Question

If one side of a squre be represented by the vectors `3hati+4hatj+5hatk`, then the area of the square is
A. 12
B. 13
C. 25
D. 50

Answer 1

Correct Answer - D
Let `a=3hati+4hatj+5hatk` then `|a|`
`=sqrt(3^(2)+4^(2)+5^(2))=sqrt(9+16+25)=5sqrt(2)`
Thus, the length of side of square`=5sqrt(2)`
Hence, area of square`=(5sqrt(2))^(2)=25xx2=50`