It helps me to think about it in opposite terms. You're increasing the radius by ~1ft (radius around the whole earth), and 2pi is the linear relationship with c

It helps me to think about it in opposite terms. You're increasing the radius by ~1ft (radius around the whole earth), and 2pi is the linear relationship with circumference, so you'll get six ft. Thinking about it this way kind of ignores the fact the circle is huge. I'm not too visual of a person though.