Răspuns:
https://sites.google.com/site/videomeditatii/clase-liceale-9-12/clasa-a-11-a-materii-de-studiu/programa-scolara-pentru-matematica-clasa-a-xi-a/aplicatii-in-geometrie-conditia-de-coliniaritate-a-3-trei-puncte-in-plan