How did Eratosthenes estimate the size of Earth in 240 B.C.?
A) by observing the duration of a solar eclipse
B) by measuring the size of Earth's shadow on the Moon in a lunar eclipse
C) by comparing the maximum altitude of the Sun in two cities at different latitudes
D) by sending fleets of ships around Earth
E) We don't know how he did it since all his writings were destroyed.

Question

Quizplus · Accepted Answer

Eratosthenes measured the maximum altitude of the Sun in two cities at different latitudes (Alexandria and Syene), and used the difference in angles to estimate the circumference of the Earth.

How Did Eratosthenes Estimate the Size of Earth in 240