If the line is straight, then only one line may connect two points.
There are 91 lines.
there are 6 lines can pass through 4 noncollinear points.
There are 20 common points.
points : infinite lines : 4 vertices : 4
One, if they're in a row.
If the line is straight, then only one line may connect two points.
the parallel lines never intercept so they do not have any common points.
There are 91 lines.
there are 6 lines can pass through 4 noncollinear points.
There are 20 common points.
3 points
points : infinite lines : 4 vertices : 4
If the two lines are actually "on top of each other", they can have infinitely many points in common. If they are parallel, they have no points in common. If they are perpendicular, they have one point in common.
45 points
If no pair of lines is parallel and if each pairwise intersection is distinct, there will be 10 points of intersection.
If no pair of lines is parallel and if each pairwise intersection is distinct, there will be 6 points of intersection.