Take the Rectangle Tool (U) and set one black triangle’s side on the inside part of the blue ring (a part of the inside ornament).
Turn it over and place one side on the inside circumference of the blue ring. The operation can be made with Free Transform option.





Make three copies of the last made layer and select Free Transform option to enlarge the copies and place them the way it is demonstrated below.
Two copies:





The third copy:



The layer’s parameters:
Blending Options>Gradient Overlay