Here I present: Euclid, The Elements’, 300BC. CONTINUED-TWO.
INTRODUCTION.
Euclid was a Greek mathematician who lived in Alexandria, EGYPT, during the reign of Ptolemy-I, placing his writing around 300 BC.
Euclid organized Greek geometry into a 13-volume set of books named The Elements’ in which the geometric relationships were derived through deductive reasoning. Thus, today’s geometry is often called Euclidean Geometry, also known as plane geometry because the relationships deal with flat surfaces.
TWO MATHEMATICAL TOOLS.
Only two (2) “mathematical tools” are required by Euclid in 300 BC of The Elements’: the compass, and straight-edge. “Straight-edges” are of a pair-of-types of “rigth triangles“. The first straight-edge is a forty-five degrees (45+45) right-triangle. The second straight-edge is a (30+60) degrees right-triangle.
HAND-FINGERS ANATOMY.
An observation of the fingers of the hand reveals Euclid’s angles of his straight-edge. The little-finger is zero (0) degrees, ring-finger is thirty (30) degrees, middle-finger is forty-five (45) degrees, index-finger is sixty (60) degrees, and the thumb is ninety (90) degrees.
