Original: Assuming that the Earth was spherical ( 360 Â ) , and that Alexandria was due north of Syene , he concluded that the meridian arc distance from Alexandria to Syene must therefore be 360 Â \/O/ 7 Â 12 ' = 1\/50 , and was therefore 1\/50 of the total circumference of the earth .
Simplified: Assuming that Alexandria was due north of Syene he concluded that the distance from Alexandria to Syene must be 1\/50 of the total circumference of the earth .