“Dynamic symmetry” is the name given by Jay Hambidge to describe a system of incommensurable ratios for proportioning areas within design compositions. In Parts One and Two of a continuing series, we surveyed the elements of root-two, -three, -four, and -five rectangular systems and, using the root-two rectangle, explored diagonals, reciprocals, complementary areas, and other techniques for composing dynamic space plans. In Part Three, we apply these techniques to the root-three rectangle and consider architectural plans by Andrea Palladio.