tl;dr: "Am I, with any given location, inside of any number of circles with varying radii"
Assume you have a database full of locations (coordinates) with arbitrary radii. Now the user enters and provides the backend with their current location.
How would the backend efficiently figure out which locations to return?
I'm having a hard time wrapping my head around this and all my googling turns up is the opposite of this (the user location provides the radius and we search for any items in the user circle).
What am I not thinking of? Do I need more coffee?