Sed contra, as pure separated Intellects, all Angels have complete and total knowledge of dancing. However, on that point, since they have no material extension, they cannot dance, so an infinite number of angels can not-dance on the head of a pin. So, infinite divided by zero.
Quod Erat Demonstratum, y'all.
It depends on which theology and when. The Renaissance speculative theology had an elementalist worldview comprising a Great Chain of Being, which transitioned fluidly from solid matter to ethereal spirit: Earth (solid), Water (liquid), Air (gas), Fire, and Spirit. In this sense, an angel that was made out of Spirit was perceived to take up some space even if their substance was more fine and less course. Similarly, a fairy was made out of Spirit thus was also able to shrink down its size − to about the size of a thumbnail. The fairy was fine, but not as fine as an angel who could shrink down even finer.
For D&D, I view the angels as constructs made out of aster, the mindstuff of the Astral Plane. The angel is pure thought, an "intellect", and lacks substance. However the angel can manifest physically within the Material Plane as a solid. To do so, the angel physicalizes via the ether of the Ethereal Plane. The ether is the fifth element that potentially comprises the other four elements. The ether itself is "spirit" as a material element. This element is the interface between the mindscape of the Astral Plane and the physicality of the Material Plane. Ether itself is pure force, including gravity. Force is energetic like fire, and fluid like water, but is itself immaterial. Ether is the element that keeps the moon and the other "stars" in their orbits. The mind of the angel manifests via the ether and physicalizes as a temporary force construct.
The Feywild and the Shadowfell are also made out of ether. Fey neighbors the Positive Plane, and Shadow neighbors the Negative Plane.
When mages "summon" spirits, such as Elemental, Fey, Shadow, Celestial or Fiend, the body that appears is a construct made out of force, aka ether.
If a person kills a Fey animal, the temporary force body vanishes but the animal is still ok. The mind of the animal reverts to its planar source, wherever that is. Similarly an angel.