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What does Euclidâs first postulate say about two points and a line?
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Euclid
Euclid, coloured woodcut, 1584. His Elements, a treatise on geometry and mathematics, is one of the most influential books ever written.
Euclidâs first postulate states that, given two points, there is a straight line that joins them. This principle serves as one of the fundamental axioms upon which Euclidean geometry is built. Later, the mathematician David Hilbert refined this concept to specify that for any two different points, there exists a unique line containing them.1