posted by Sarah .
How far above the surface of Earth would you weigh 63.6 percent of your surface weight?
If the new radius is R, and the earth's radius is r,
.636 * Mmg/r^2 = = Mmg/R^2
.636/r^2 = 1/R^2
R = r/.797 = 1.25r
plug in your favorite value for r, and figure the difference