how theycalculated the radius or the diameter of the earth.?

Question

it is said that the diameter is12,800 i need to know how

Answer 1

Eratosthenes first calculated the radius of the Earth using an ancient measurement of distance called the stadium. He noticed that the sun's rays illuminated the bottom of a deep well in the city of Syene in Upper Egypt when the sun was at the highest point in the sky (noon at the summer solstice). In Alexandria, which was at a distance of 5,000 stadia from Syene, the sun was at an angle of 7.5º from the vertical. Eratosthenes assumed that the sun's rays were parallel because it was so far away. In 240 B.C., he calculated the Earth's radius to be 250,000 stadia. Unfortunately, historical records are not detailed enough for us to determine the length of a stadium exactly. However, it is thought that Eratosthenes' estimate was relatively close, being larger by 15 - 20%.
You can calculate the radius of the Earth yourself, the next time you are on a beach facing west, such as in California or western Florida. You will need good weather to provide a clear view of the sunset. Lay down on the beach on your stomach until you see the last rays of the sun disappear from behind the horizon. Start your stopwatch and stand up quickly. You will see the sun again for about another 12 seconds or so. When the sun sets for the second time, stop your watch. To calculate the radius of the Earth in kilometers, multiply 550,240 by your height in meters, and divide by the time squared. That should give you an answer to within 15%.

Answer 2

Trigonometry. in case you word a much off merchandise from a typical top above sea point then the perspective at which you word this is top tells you the way some distance under the horizon it is (tangent line) of direction you ought to comprehend distance to the article and this is top. of direction at present you may actually degree the curvature of the earths floor at very extreme selection (we even have satellites in orbit that comprehend the place one yet another are (very wisely and could degree the gap to the earths floor to interior centimeter accuracy)

Answer 3

Well the diameter is closer to 7900 and they probably calculated it using measurements from satellites. Google it and do some hunting on the internet, and you will find the answer.

Answer 4

ancient greek mathematicans found the radius of the earth to a few miles by using mechnical instruments and using the trigonometric laws. i think a few other ancient people could do this as well. now satellitles do it by the law of triangulation.

Answer 5

measuring tape......they got the minorities in improvished(i think this is a word)...nations to to do this...they promised them food and clothes but only gave them slow death ...but hope was on their minds .....it was a ploy to increase the female to male ratio so that western countries would allows 2 female to 1 male marriages.

Answer 6

By using shadows my friend.