Ferromagnetic resonance (FMR) measurements on the magnetic quasi-one-dimensional systems (C6H11NH3) CuCl3 (CHAC) and (C6H11NH3)CuBr 3 (CHAB) in the region 8< nu <75 GHz and at a temperature of 1.25K are presented. The experimental results can be described quite well by a classical mean-field model assuming that, in a first approximation, the ferromagnetic chains behave like independent entities. A comparison of this model with the experimental results yields accurate values for the exchange anisotropy. These values indicate a pronounced easy-plan anisotropy for CHAB, whereas for CHAC the inferred anisotropy is clearly orthorhombic. These results are in fair agreement with previously reported measurements of magnetisation and specific heat.