
Fig 1. Create a circle on a transparent layer and Fill it with white. Be sure View > Rulers is checked. Turn off Background layer.
Fig 2. Edit > Transform > Scale. It will present a center mark
Fig 3. Drag out reference lines from the top and side rulers across the center mark. With that done you no longer need the Transform lines in Step 2, so do not Commit
Fig 4. Use the Rectangular marquee tool to draw the rectangle shown. Cmd+J to put the section on its own layer
Fig 5. Lock the transparent area by clicking on the symbol in the Layers panel. Then Edit > Fill with a color
Step 6. Return to the circle layer and repeat Step 4 for the remaining 3 segments. Then use the Move tool to straddle the reference lines and return each to its ruler.
