Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Persian unit | Persian name | Relation to previous unit | Metric Value | Imperial Value |
| --- | --- | --- | --- | --- |
| finger | aiwas |  | ≈ 20 mm | ≈ 0.8 in |
| hand | dva | 5 aiwas | ≈ 100 mm | ≈ 4 in |
| foot | trayas | 3 dva | ≈ 300 mm | ≈ 1 foot |
| four-hands | remen | 4 dva | ≈ 400 mm | ≈ 16 in |
| cubit (five-hands) | pank'a dva | 5 dva | ≈ 500 mm | ≈ 20 in |
| great cubit (six-hands) | (k)swacsh dva | 6 dva | ≈ 600 mm | ≈ 2 ft |
| pace | pank'a | 5 trayas | ≈ 1.5 m | ≈ 5 ft |
| ten-foot | daca trayas | pank'a | ≈ 3 m | ≈ 10 ft |
| hundred-foot | chebel | 8 daca trayas | ≈ 24 m | ≈ 80 ft |
| league, the distance a horse could walk in one hour. | parasang | 250 chebel | ≈ 6 km | ≈ 3.75 miles |
| mansion, one day's march on the Royal Road. | (Greek stathmos) | 4 or 5 parasang | ≈ 24–30 km | ≈ 14–18 miles |
Question:
how long is four hands in the metric system?
Answer:
≈ 400 mm