Plate

grabcad

I started with a sketch of a circle on the front plane and used the offset entities tool to create the smaller profiles inside. Then I sketched various circles that would act as arcs to guide my model and dimensioned them to create the spoke with the negative space. After extruding each profile to the correct depth, I used the circular pattern tool to rotate the spokes around 360 degrees with nine duplicated profiles. For the smoothed out back edge, I started a sketch on the top plane to make the initial cut, then revolve cutting that sketch 360 degrees around the full profile.