Angular size

Angular size is a measurement of how large or small something is using rotational measurement. It is useful for measuring things that are so far away that they appear two-dimensional.It is easy to understand angular size by imagining that you're standing some distance from some kind of large landmark, like the Golden Gate Bridge. Hold out your arm and point to one end of the bridge, then — without moving your arm with respect to your body — turn your body slightly so that you are now pointing to the other end of the bridge.
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