HSG-GMD.B.4 has to do with a student’s ability to visualize relationships between 2 and 3 dimensional objects. Given the example above you see that a 3-dimensional sphere is related to a 2-dimensional circle. This relation is this; a circle is the cross-section of a sphere. No matter where or at what angle you take the cross-section it will be a circle and not matter the size of the sphere is will be a circle as seen by the rings in the cross-section. This could be better represented with 3 spheres cut in different places showing that the resulting cross-section is always a circle.