You cannot associate volume and length. However, I'll take it you meant to say decametres. There are 10000 millimetres in a decametre. To get the answer here, you find the inverse of 10000. In other words 1/10000 is 0.0001 decametres.
One US gallon is 0.3785 decaliters.
There are 0.1 decaliters in one liter.
A decaliter is 10 liters, so one tenth.
6.54kL is equal to 654 decaliters.
10 decaliters per hectoliter.
25 decaliters is 250000mL
70.73 hectoliters is 707.3 decaliters.
Two decaliters is 20 liters.
0.00085 liters is 0.000085 decaliters.
123mL is equal to 0.0123 decaliters.
500 ml equates to 0.05 decaliters.
295mL equates to 0.0295 decaliters.