Eratosthenes Measured the Radius of Earth By

Multiple Choice

Eratosthenes measured the radius of Earth by:

A) timing the disappearance of the Sun at sunset for two different positions on Earth on the same day of the year.
B) estimating the size of the shadow of Earth on the Moon during a lunar eclipse.
C) measuring the angular position of the pole star from several positions on Earth.
D) noting the different angles of the Sun at midday on the same day of the year at different positions on Earth.