Assuming that the Earth was spherical ( 360 ° ) , and that Alexandria was due north of Syene , he concluded that the meridian arc distance from Alexandria to Syene must therefore be 1\/50th of a circle 's circumference , or 7 ° 12 ' \ / 360 ° .
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 ( 360 degrees ) .