To estimate the value of \( 6 \times \sqrt{2} \), we need to know the approximate value of \( \sqrt{2} \).
The value of \( \sqrt{2} \) is approximately 1.414.
Now we can calculate:
\[ 6 \times \sqrt{2} \approx 6 \times 1.414 = 8.484 \]
Now, we need to compare this result to the provided options:
- 6.4
- 7.1
- 9.8
- 8.4
The closest estimate to 8.484 is 8.4.
So, the best estimate is 8.4.