The numbers given are for guidance. We can give you the length of a carbon carbon single bond, and if you study thousands of molecules with carbon-carbon single bonds you will see that there is some variance, because the presence of other nearby atoms changes the length.
C-C , 1.54 angstroms
C-H , 1.09 angstroms
C-O , 1.16 angstroms
O-H , 0.96 angstroms
Rob Sterling 