THALES OF MILETUS

Thales of Miletus (pronounced /ˈθeɪliːz/; Greek: Θαλῆς, Thalēs; c. 624 BC – c. 546 BC) was a pre-Socratic Greek philosopher from Miletus in Asia Minor, and one of the Seven Sages of Greece. Many, most notably Aristotle, regard him as the first philosopher in the Greek tradition.^[1] According to Bertrand Russell, "Western philosophy begins with Thales."^[2] Thales attempted to explain natural phenomena without reference to mythology and was tremendously influential in this respect. Almost all of the other pre-Socratic philosophers follow him in attempting to provide an explanation of ultimate substance, change, and the existence of the world -- without reference to mythology. Those philosophers were also influential, and eventually Thales' rejection of mythological explanations became an essential idea for the scientific revolution. He was also the first to define general principles and set forth hypotheses, and as a result has been dubbed the "Father of Science".^[3][4]

In mathematics, Thales used geometry to solve problems such as calculating the height of pyramids and the distance of ships from the shore. He is credited with the first use of deductive reasoning applied to geometry, by deriving four corollaries to Thales' Theorem. As a result, he has been hailed as the first true mathematician and is the first known individual to whom a mathematical discovery has been attributed.
Referred from Wikipedia

TRIANGLES AND QUADRILATERALS (Part 1)

Thales of Miletus, knew that the measurements of a triangle were fixed when the length of its base and the sizes of its basebase angles were known. He used this fact to determine the distance of a ship at sea. Pythagoras of Samos, who settled eventually in Crotona, develoved  the theory of congruent triangles. It was probably in his school at Crotona that the congruence theorems were first analysed and related to one another in some kind of logical order.

During the life time of Plato (429-348 B.C.) Athens became the chief center of mathematical studies. It held supremacy for about 150 years, when the first university in the world, at Alexandria, displaced it. Plato was born near Athens of rich and noble parents. He studied in Egypt, Cyrille, and Italy, returning to Athens about 380 B.C. About a mile outside Athens was a beautiful walled garden called Academia, after its owner Academos. Here Plato formed a school of students which came to be known as the Academy. Plato was a philosopher who believed in geometry as one of the foundations of a liberal education. The inscription over the entrance to the academy ran 'Let none ignorant of geometry enter my door'. Plato did great service to mathematics in making its foundations logical and secure. We still tend to regards the compasses and ruler as the chief mathematical instruments largely because he would allow no other instruments to be used.

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