The are and hectare fill an awkward gap between the square metre and the
square kilometre. The ratio of the two is 1:10^6 so there is really room
for a unit between them. If the intermediate unit was 10^3 m^2, it would
represent an awkward area - a square with sides of length 10*10^2 m
(approx
31 m). Alternatively it could be defined as a "metric acre" - a strip 100
m
long and 10 m wide. Neither is particularly satisfactory. An awkward
situation all round.
I see a certain logic in these units:
linear
1 dam = 10 m
1 hm = 10 dam
1 km = 10 hm
common factor 10
Area
1 are = 100 m^2
1 ha = 100 are
1 km^2 = 100 ha
common factor 10^2
Volume
1 L = 1000 mL
1 m^3 = 1000 L
common factor 10^3
I'm not suggesting that they should all be retained but it's interesting to
note the underlying pattern
Phil Hall
