To determine the sign of the product \(-16.8 \times \frac{3}{7}\), we can analyze the signs of the individual factors:
- \(-16.8\) is negative.
- \(\frac{3}{7}\) is positive.
When multiplying a negative number by a positive number, the product is negative.
Therefore, the sign of the product \(-16.8 \times \frac{3}{7}\) is negative.