To determine the sign of the product of \(-16.8\) and \(\frac{3}{7}\), we need to consider the signs of the numbers involved:
- \(-16.8\) is negative.
- \(\frac{3}{7}\) is positive.
When you multiply a negative number by a positive number, the product is always negative.
Therefore, the sign of the product \(-16.8 \times \frac{3}{7}\) is negative.