Asegmentdesignatesa portionof a line that has two endpoints.Segmentsare namedby their endpoints.
NotationNotes: Just like lines,segmentsare writtenwith two capitalletters.For segmentswe use a bar
on top with no arrows.Segmentscan also be namedin any order, so the segmentabovecouldbe named
or.Arayis a portionof a line that has only one endpointand extendsinfinitelyin the otherdirection.Raysare
namedby their endpointsand anotherpointon the line. The endpointalwayscomesfirst in the nameof a
ray.
Like segments,rays are namedwith two capitalletters,and the symbolon top has one arrow. The ray is
alwaysnamedwith the endpointfirst, so we wouldwrite for the figureabove.
Anintersectionis the pointor set of pointswherelines,planes,segments,or rays crosseachother. Inter-
sectionsare very importantsinceyou can studythe differentregionsthey create.
In the imageabove, is the pointof intersectionof and. is the intersectionof and
.Example 3
Whichgeometricobjectbest modelsa straightroad connectingtwo cities?