Math problem! I don't get a word. Help please?

It is simply the difference between the ciferences of 2 circles with different radii. Cirference is 2x pi x rad. Say the planet was 1000000ft rad equation would be 2x1000000x3.14, cirference traced by head would be 2x1000005.5x3.14, subtract smaller from larger. All you have to do is find earth's radius in feet and substitute in equations.