1) First, we must remember the definition of a decametre (1 dam) in terms of meters (1 m):
And also the definition of a millimetre (1 mm) in terms of meters (1 m):
![1\operatorname{mm}=0.001m]()
2) Now, we are ready to do the calc. We simply divide 760,854 millimetres by 1 decameter and then we replace by the definition of each unit in terms of its value in meters:
![\frac{760,854\operatorname{mm}}{1\text{dam}}=760,854\cdot\frac{1\operatorname{mm}}{1\text{dam}}=760,854\cdot(0.001m)/(10m)=760,854\cdot0.0001=(760,854)/(10000)=76.0854]()
Answer = 76.0854
We have 76.0854 decametres in 760,854 millimetres.