A person six feet tall walks around the earth. How many feet farther does the top of this person's head travel than the bottoms of his feet? Express your answer in terms of power.

If we use 4000 miles for the Earth's radius, the circumference is 2*pi*4000=8000*pi

The radius to the person's head, using 6 feet as 1/880 mile, is 2*pi*4000 (1/880) = 8000 * (2/880) * pi

The difference is pi (8000 2/880) - 8000=2pi/880 miles

This is 12 pi feet.

not knowing the diameter of the earth:

circumference of a sphere is C=2*PI*r

adding the height of the person the circumference would be 2*PI * (r+6)

wanting the difference between the two you know would have

2*PI (r+6) - 2*PI*r

which gets reduced to 12PI

if you need it in power 12 * 3.14 = 37.68 = 3.78 x 10^1

depending on the value used for pi answer may be slightly different.