Definition: Collinear Points, Segments, Rays
Points, segments or rays, which lie on the same straight line are called collinear or straighton.
Mentioned in:
Definitions: 1
Lemmas: 2
Proofs: 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Propositions: 20 21 22 23 24 25
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References
Adapted from CC BYSA 3.0 Sources:
 Callahan, Daniel: "Euclidâ€™s 'Elements' Redux" 2014
Adapted from (Public Domain)
 Casey, John: "The First Six Books of the Elements of Euclid"