Suppose you are still a two-dimensional being, living on the same sphere of radius R. Show that if you draw a circle of radius r, the circle's circumference will be
C=2πRsin(r/R).(3.62)
Idealize the Earth as a perfect sphere of radius R=6371 km. If you could measure distances with an error of ±1 meter, how large a circle would you have to draw on the Earth's surface to convince yourself that the Earth is spherical rather than flat?