Is decameter and hectometer common length units in Romanian? I've never heard of it before being used in English...
Well I can't speak for Romania, but here in France we use those units, most of the time at school, to convert one unit to another for example(Same for the weights, btw. Décagramme, hectogrammes, etc...). We also have a tool to measure length and it is called 'décamètre'.
alternative spellings should be accepted: in British English, "metru" is "metre" Therefore hectometre should not be rejected.
Milli- = 1/1000; Centi- = 1/100; Deci- = 1/10; Deca- = 10; Hecto- = 100; Kilo- = 1000
One hectometer is equivalent to 100 meters. It's pretty self-explanatory.