Answer:
Number of points, x, Number of segments, y
x: 2, 3, 4, 5, ... N,. ...
y: 1, 3, 6, 10, ... (N-1)(N)/2, ...
Step-by-step explanation:
Adding Nth point, there are N-1 new segments,
and (sum over {i = 1 to N-1} of i) total segments. As Gauss knew when he was c.10 yo, the sum is (N-1)(N)/2.
.