Who calculated the circumference of the earth trignometrically?
n the 200s BC, Eratosthenes figured out a very clever method for measuring the size of the Earth. He heard about a well in Syene (in modern Egypt) where the sunshine reached the bottom only at noon in the summer solstice. So he knew exactly when the sun was directly overhead. Further north in Alexandria he put a stick straight up in the ground and measured the angle of its shadow at that precise moment as 7.2°. It meant that the distance from Syene to Alexandria was 7.2/360 of the Earth’s circumfrence. Since he knew this distance, he could compute the circumfrence as 39250km, a diameter of about 12500km.n the 200s BC, Eratosthenes figured out a very clever method for measuring the size of the Earth. He heard about a well in Syene (in modern Egypt) where the sunshine reached the bottom only at noon in the summer solstice. So he knew exactly when the sun was directly overhead. Further north in Alexandria he put a stick straight up in the ground and measured the angle of its shadow at tha
