To convert metric tons to kilograms, you can use the conversion factor that 1 metric ton is equal to 1,000 kilograms.
Given:
\[ 4.2 \text{ metric tons} \]
To find the equivalent weight in kilograms, you multiply the number of metric tons by the number of kilograms per metric ton:
\[ 4.2 \text{ metric tons} \times 1,000 \text{ kg/metric ton} = 4,200 \text{ kg} \]
So, 4.2 metric tons is equal to 4,200 kilograms.