The given complex $[\text{Pt}(\text{Py})(\text{NH}_3)\text{BrCl}]$ is a square planar complex of the type $[Mabcd]$ (or $MABXL$), where all four ligands are different unidentate ligands. According to coordination chemistry principles, such a complex exhibits three geometrical isomers (two cis and one trans). These can be determined by fixing one ligand at a specific position and placing the other three ligands trans to it one by one .