A warehouse inspection robot leaves its charging base, drives four legs of a patrol, and stops. Its log records each leg as a displacement vector in metres. When the log is read back, one row has been corrupted:
| Leg | Displacement (m) |
|---|---|
| 1 | |
| 2 | |
| 3 | corrupted |
| 4 |
The patrol's endpoint survived, though. A GPS fix taken after the robot stopped puts it at
metres relative to the base, measuring east and north from the base as the origin.
How long was the corrupted leg 3?
Answer in metres, rounded to two decimal places.