How to identify x,y coordinates that lie within a closed polygon whose vertices are defined by x,y coordinates

I have a set of shapes in a field, each with known x,y coordinates, height and width.

I wish to select a subset of these shapes whose centres lie within a closed polygonal line with known coordinates to its vertices.

I program in  VBA and unfortunately am not multi-lingual. However, given the principles, I'd hope to progress to write it in vba.

Can someone please help / point me to accessible resources?

Thanks!
Kelvin4