I would use Feet or Miles.
the appropriate metric unit for the height of a giraffe.is m
When measuring the height of a giraffe, you should use the most common SI unit for height: The Giraffe. The average height of a giraffe is one giraffe. One giraffe translates to 5.45 metres, 17 feet 10.5 inches, or 0.07 jumbo jets.
To measure the height of a flagpole. you would use the Meter.
cm or Feet
Metres (American spelling = meters), unit symbol "m", would be the most appropriate metric unit to measure the height of a 32-story building.
Feet or inches
You would use meters to measure the height of a building.