### Question --- How did the Greeks determine the size of the Earth and the distance to the Moon? ### Answer --- ![[History of Earth-Moon-Sun Units#Deriving Units & Conversions Earth Radius ($R_{ oplus}$) Earth Radius]] ![[History of Earth-Moon-Sun Units#Deriving Units & Conversions Lunar Radius ($R_{ rm Moon}$) Lunar Radius & Units & Conversions Earth-Moon Distance ($D_{ rm EM}$) Earth-Moon Distance]]