r=radius of earth in feet

circumfrence=pi*2*r

lg = (pi*(r+1)*2) - (pi*r*2)

lg = pi((r+1)*2 - r*2)

lg = 2pi((r+1) - r)

lg = 2pi(r+1-r)

lg = 2pi(1)

lg = 2pi

lg = 2*3.14

lg = 6.28

It's unintuitive that it doesn't matter what the radius is.