To estimate the value of \( 6 \times \sqrt{2} \), we first need to know the approximate value of \( \sqrt{2} \). A good approximation for \( \sqrt{2} \) is about 1.4.
Now we can calculate:
\[ 6 \times \sqrt{2} \approx 6 \times 1.4 = 8.4 \]
Among the given choices, the best estimate for \( 6 \times \sqrt{2} \) is 8.4.