Answer :
Eratosthenes built a pole in Alexandria, where he observed that it produced a shadow on the summer solstice, demonstrating that the Sun was not exactly overhead but rather pointed slightly south. Eratosthenes was able to determine the circumference of the earth by understanding the curvature of the Earth and knowing the separation between the two towns.
Using this example, you can see how Eratosthenes determined the Earth's circumference in real life. Eratosthenes measured the length of the shadow cast by an Alexandrian column of known height at noon on the summer solstice. He could calculate the angle between them using these two lengths ().
Only one astronomical object—Earth, which is third from the Sun—is known to support life. Although the Solar System contains enormous amounts of water, only Earth is home to liquid surface water. The oceans cover around 71% of Earth's surface, dwarfing its lakes, rivers, and polar ice.
To know more about Earth's circumference refer to: https://brainly.com/question/895938
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