Answer:
![\boxed {\boxed {\sf 2 \ significant \ figures}}](https://img.qammunity.org/2021/formulas/mathematics/college/mol7njil48r7dsyzr6puq72nzyncjbkdf5.png)
Explanation:
According to the "rules" of significant figures, all the zeroes to the right of the final non-zero number are not significant, unless there is a decimal point.
We are given the measurement:
84,000 kg
If there was a decimal point (84,000.0 kg), then there would be 5 significant figures.
Since there isn't a decimal point, all 3 zeroes to the right of the number 4 aren't significant. The 8 and 4 are significant, so there are 2 significant figures.