https://en.wikipedia.org/wiki/EratosthenesHe made five important assumptions (none of which is perfectly accurate):[17][18]
That the distance between Alexandria and Syene was 5000 stadia,
That Alexandria is due north of Syene
That Syene lies on the Tropic of Cancer
That the Earth is a perfect sphere.
That light rays emanating from the Sun are parallel.
The last assumption is vastly wrong as well because we can see light rays are locally crepuscular and during the eclipse NASA said the sun ray are actually converging to create a 70- miles wide shadow. How is it a supposed 2000 mile wide object only creates a 70 miles shadow on the earth during a solar eclipse but during a lunar eclipse the shadow of the earth covers the entire moon?
Holy Circle Logic Batman!
Trig IS hard.