Now, choose n (different) points on a line. Find the number of segments that can be formed using these points as endpoints of segments. (Hint: Complete the table and observe the pattern.)
<--•-------•--> <--•--•-------•-->
P Q P R Q

<--•--•-----•--•--> <--•--•---•----•--•-->
P R S Q P R T S Q
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