Apart of a line that starts at one endpoint and extends forever in one direction is a(n):

A part of a line that starts at one endpoint and extends forever in one direction is a(n):  RAY

Ray--

A ray is a part of a line that starts at a point and goes infinitely in any direction to infinity i.e. there is no end point for the other end. i.e. it is called a line with one end-point.

Also, it use two undefined terms of mathematics: Point and Line.

Two ray starting with the same end-point and going to different direction form an angle.

triangle abc is reflected on the line x=-6.5 then reflected again on the x axis

step-by-step explanation: