The Earth's circumference was first determined by:
A)Aristotle using lunar eclipses.
B)Pythagoras with geometry.
C)Hipparchus with stellar parallaxes.
D)Erastothenes with solstice shadows.
E)Aristarchus with first and third quarter Moon timings.

Question

Quizplus · Accepted Answer

Erastothenes measured the differences in the angles of shadows at noon on the summer solstice in Alexandria and Syene (now Aswan), and used this data to calculate the Earth's circumference. Eratosthenes measured the angle of shadows cast by the sun at two different locations and used simple geometry to calculate the Earth's circumference.

The Earth's Circumference Was First Determined By