What is the circumference of the earth according to Eratosthenes?
Values between 500 and about 600 feet have been suggested, putting Eratosthenes’ calculated circumference between about 24,000 miles and about 29,000 miles. The Earth is now known to measure about 24,900 miles around the equator, slightly less around the poles.
What did Eratosthenes use to measure the circumference?
Eratosthenes hired a man to pace the distance between the two cities and learned they were 5,000 stadia apart, which is about 800 kilometers. He could then use simple proportions to find the Earth’s circumference — 7.2 degrees is 1/50 of 360 degrees, so 800 times 50 equals 40,000 kilometers.
How did Eratosthenes measure the size of the Earth in 240 BC?
He measured the length of the shadow of a tall tower in Alexandria, and used simple geometry to calculate the angle between the shadow and the vertical tower. This angle turned out to be about 7.2 degrees.
What is the circumference of Earth?
24,901 miEarth / Circumference
How did Eratosthenes estimate the size of Earth quizlet?
Eratosthenes measured the circumference of the earth by measuring the distance between two cities. Then he measured the angle of sunlight relative to the vertical on the summer solstice. The sun was overhead in Alexandria but seven degrees away from the vertical in Syene.
What was Eratosthenes experiment?
Eratosthenes analyzed the observations with the assumption that the earth is a sphere and the sun is very far away. The geometry of the situation is sketched at the right. He concluded that the circumference of the earth was about 50 times greater than the distance from Alexandria to Aswan.
How did they find the circumference of the earth?
Eratosthenes sent a man to Syene from Alexandria on foot to measure the distance between Alexandria and Syene. Thus, Eratosthenes measured the distance between the two cities is 800 km. He multiplied by 800 km to 50 and calculated that the Earth’s circumference is 40,000 km.
How do I figure circumference?
To calculate the circumference of a circle, multiply the diameter of the circle with π (pi). The circumference can also be calculated by multiplying 2×radius with pi (π=3.14).
How did Eratosthenes measure the circumference of the Earth quizlet?
Which place is center of Earth?
In 2003, a refined result was yielded by Holger Isenberg: 40°52′N 34°34′E, also in Turkey, near the district of İskilip, Çorum Province, approx. 200 km northeast of Ankara. In 2016, Google Maps marked Isenberg’s result of 40°52′N 34°34′ECoordinates: 40°52′N 34°34′E as the geographical center of Earth.
Who found the circumference of the earth?
Eratosthenes
This illustration shows how Eratosthenes actually calculated the circumference of the Earth. At noon on the summer solstice, Eratosthenes measured the length of the shadow cast by a column of known height at Alexandria. With these two lengths, he could solve for the angle between them (θ).
How big was Eratosthenes’crater?
The Eratosthenes impact crater on the surface of the moon, measuring 58 kilometres in diameter, circa 1990. Portrait of Eratosthenes of Cyrene , Greek mathematician, astronomer and poet, engraving.
What did Eratosthenes do?
Eratosthenes was a Greek scientific writer, astronomer, and poet, who is credited with making the first approximation of the size of the Earth for which any details are know. He was born in Cyrene, Libya c. 276 BC. After studying in Alexandria and Athens, he settled in Alexandria around 255 BC and became director of the Great Library there.
How did Eratosthenes use trigonometry in his work?
By measuring the length of the shadow cast, and with the known length of the stick from the ground up, Eratosthenes was then able to use basic trigonometry to figure out the angle of the imaginary triangle drawn by the shadow and the length of the stick.