Introduction to Euclid's Geometry

Egypt, Babylonia, India, Greece, China

Geometry was studied in various forms in many ancient civilizations including Egypt, Babylonia, China, India, Greece, and the Incas. Each civilization developed geometry to solve practical problems.

Point, Line, Plane

Point, line, and plane are kept as undefined terms in geometry because defining them leads to circular definitions. We understand them intuitively and represent them with physical models.

Axiom 1

This is Euclid's first axiom. It means if A = C and B = C, then A = B. This is the transitive property of equality.

A straight line may be drawn from any one point to any other point

Euclid's first postulate tells us that we can always draw a straight line between any two points. This establishes the basic construction ability in geometry.