For observers on the ground with eye-level at h = 5 ft 7 in (5.583 ft), the Horizon appears at a distance of 2.89 miles.
http://en.wikipedia.org/wiki/Horizon
Science says the Horizon is a curvature. "Did I lose you yet?"
A curvature is an arch. "Did I lose you yet?"
According to the source web page above, the Horizon would appear at a distance of 2.89 miles, on a Round Earth the observer would always be standing at the top center of an arch, so we must multiply that distance by 2 to get the full length of the arch. One degree of a circle is an arch.
2.89 mi * 2 = 5.78 miles.
This arch is 5.58 mi and represents 1 degree of the supposed Round Earth.
Lets multiply the length of the arch by 360 to get the circumference of the Earth.
5.78 mi * 360 = 2080.8 miles = circumference of the Earth = HAHAHA....ROTF...HAHAHA....LOL.....HAHAHA.