Hersehel (1813) The name of Thales
(about 600 B C ) is invariably associated with height and distance problems He
is credited with the determination of the height of a great pyramid in Egypt by
measuring shadows of the pyramid and an auxiliary staff (or gnomon) of known
height, and comparing the ratios:
H
S
=sh
 = tan (sun’s altitude)
Thales is also said to have calculated the distance of a ship at sea through
the proportionality of sides of similar triangles