An Etymological Dictionary of Astronomy and Astrophysics

Put in modern notation, if α and β are acute angles and if β <α, then sin α / sin β <α / β < tan α / tan β. Aristarchus probably used this inequality to show that the Sun is between 18 and 20 times as far from the Earth as the Moon is.

See also: Aristarchus of Samos (c.310-c.230 BC); → inequality.