Because of Geometers scarcity, I was instigated to republish this article and to locate the weakness of proving this Axiom. Weakness created the Non-Euclid geometries which deviated GR in Space-time confinement, so, not conceiving the beyond Plancks existence, not explaining the WHY speed of light is constant, and thus the whole universe. In the manuscript it is proved that parallel postulate is only in Plane (three points only and not a Spherical triangle ) based on the four Postulates for Constructions, and now is proved to be a Theorem, where all properties of Euclidean geometry compactly...