I need some math help

Hi All,
let me start by saying that I am horrible at math and I am in some dire need of help. I have a bunch of objects on the stage and I’m trying to find out if the center of the smaller objects is inside a larger one. Please see attached illustration.

the x’s mark the centers of the objects. I’m trying to find which of the black objects’ centers are within the larger blue object. eventually I’ll need to move them to a point on the blue objects perimeter, but if I can some help with this it will be a huge step in the right direction. Please let me know if that makes sense or not.

Much appreciation.