Video narration
Mili: On our school map, what kind of straight path connects the gate to the classroom? Mili: Let's mark the gate A and the classroom B. Join them with one straight path; that is a line segment. It has two fixed endpoints, A and B, and we can name it AB or BA. Arin: Now watch the turn. Extend the same path beyond A and B, endlessly in both directions. No endpoints remain. That is a line. Mili: So inspect the ends: fixed endpoints mean line segment; arrows continuing both ways mean line. Arin: Back on the school map, this connection shows the difference. Mili: Ready? Two fixed endpoints-what is it? [pause] Line segment! Now arrows both ways-what is it? [pause] A line! Arin: The gate-to-classroom path is a line segment when it stops at A and B. Extend it forever both ways: a line. You're ready for the Geometry Path Master Challenge!