<P> In geometry, a line segment is a part of a line that is bounded by two distinct end points, and contains every point on the line between its endpoints . A closed line segment includes both endpoints, while an open line segment excludes both endpoints; a half - open line segment includes exactly one of the endpoints . </P> <P> Examples of line segments include the sides of a triangle or square . More generally, when both of the segment's end points are vertices of a polygon or polyhedron, the line segment is either an edge (of that polygon or polyhedron) if they are adjacent vertices, or otherwise a diagonal . When the end points both lie on a curve such as a circle, a line segment is called a chord (of that curve). </P> <P> If V is a vector space over R (\ displaystyle \ mathbb (R)) or C (\ displaystyle \ mathbb (C)), and L is a subset of V, then L is a line segment if L can be parameterized as </P> <Dl> <Dd> L = (u + t v ∣ t ∈ (0, 1)) (\ displaystyle L = \ (\ mathbf (u) + t \ mathbf (v) \ mid t \ in (0, 1) \)) </Dd> </Dl>

A polygon of 10 line segments has __ vertices