Given that 4 points A, B, C, D are on the same line. How many segments are there?

Given that 4 points A, B, C, D are on the same line. How many segments are there?

1) Give that 4 points A, B, C, D are on the same line. How many segments are ther?

Given two parallel lines xy & zt. Three points A,B & C are on line xy, two points D & E are on line zt. Draw lines passing through the pairs of points. How many lines are there? (including xy & zt) 

There are 2015 distinct points on the line d:  ... ,. A point M is not on the line d. Match M to  ... ,. How many triangles are there?
Answer:There are  triangles.

given a parallel line xy and zt. Three point A,B,C are on line xy, two point D,E are on line zt. Draws line passing through the pair of point. How many lines are there?

Given 100 points with any 3 points non-aligned. Draw all the line passing through any 2 of these points. How many lines are there?
 

Given 100 points with any 3 points non-aligned. Draw all the line passing through any 2 of these points. How many lines are there?

Given 20 points. Draw the lines through the 2 points of these 20 points. How many lines are there if only 3 of 20 points are aligned?