  This work focuses on decomposition of isospin amplitude of D meson
non-leptonic decays. Isospin vector algebra is used to show the equivalency of
two amplitude decompositions. We restrict to the transitions involving only Del
I = 1 and Del I = 0: The isospin symmetry is relating charge channel (D+ ->
K+,Pi+ Pi-; D+ -> K+, Pi0, Pi0 and D+-> K0, Pi0,Pi+); and neutral channel (D0
-> K0,Pi+,Pi- D0 -> K0, Pi0, Pi0 and D0 -> K+, Pi0, Pi-) with each other.
Equivalent triangle relations are obtained for both channels.
