Radius is a meaningful word packed with purpose. Two definitions are important to point out. The first is the unscientific definition: a straight line extending from the center of a circle or sphere to the circumference or surface.
Pretty boring definition; (reading definitions are always boring). But the scientific definition packs much more about the meaning that ties it effectively into loving your neighbor.
A line segment joins the center of a circle or sphere with any point on the circumference of the circle or the surface of the sphere. It is half the length of the diameter.
You are the circle's center joining with the neighbors within your radius. The line segment that joins you with the neighbors within your radius is the proactive efforts to reach out to your neighbors.