Captain Picard said his ship was 1.235 km long while Commander Worf said it was actually 125,300 cm long. Whose length is the longest when measured in meters? How much longer?
Worf's measurement is 18 meters longer than Picard's.
Captain Picard's measurement is in kilometers, and there are 1000 meters per kilometer, so
Commander Worf's measurement is, for whatever reason, in centimeters, and there are 100 centimeters per meter.
When both measurements are converted into meters, it's easy to compare them and see which one is longer - Worf's.