παραλληλόγραμμον: Difference between revisions

In Euclidean geometry, a parallelogram is a simple (non-self-intersecting) quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure. The congruence of opposite sides and opposite angles is a direct consequence of the Euclidean parallel postulate and neither condition can be proven without appealing to the Euclidean parallel postulate or one of its equivalent formulations.

|ptext=[[https://www.translatum.gr/images/pape/pape-02-0488.png Seite 488]] τό, das Parallelogramm, eine Figur, die von vier Linien eingeschlossen ist, deren zwei und zwei einander gleichlaufen, Euclid. u. A. – Adjectivisch bei Plut. adv. Stoic. 39, wie [[παραλληλόγραμμον]] [[σχῆμα]] Strab.