Before we begin, some facts I googled:
The radius of the Earth is about 4000 miles
The circumference of the Earth is about 25000 miles
The formula to calculate circumference is 2 * pi * radius
Now, there isn't a single answer for your question because it depends on how far you walk. We'll let f represent how far your feet move and h how far your head moves. Given f and the circumference of the Earth, the angle (a) that you walked can be calculated by f/a = 25000/360 (There are 360 degrees in a circle, if you walked half the circumference of the Earth the angle would be 180). Solved for a you get a = f * 0.0144. The equation that your head moved (h) is h/a = 25158/360 (We got 25158 by having the circumference of the circle that you head moved as 4006 (Earth's plus the height of the man) * 2 * pi (the formula for circumference). solved for h you get h = a * 69.88. We already solve for a (a = f * 0.0144), substituting this in and simplifying we get our formula: h = f * 1.006
