Answer :

To estimate the value of [tex]\( 6 \times \sqrt{2} \)[/tex], we will follow these steps:

1. Approximate the value of [tex]\( \sqrt{2} \)[/tex]:
The square root of 2, [tex]\( \sqrt{2} \)[/tex], is approximately 1.414.

2. Multiply 6 by [tex]\( \sqrt{2} \)[/tex]:
We need to find the product [tex]\( 6 \times 1.414 \)[/tex].

3. Perform the multiplication:
[tex]\[ 6 \times 1.414 = 8.484 \][/tex]

4. Compare the result with the given choices:
- 8.4
- 7.1
- 9.8
- 6.4

The value 8.484 is closest to 8.4 among the given choices.

Therefore, the best estimate for [tex]\( 6 \times \sqrt{2} \)[/tex] is 8.4.