Why there must be at least two lines on any given plane.
If three or more points are on a straight line, the points are said to be collinear points.
Answer: Since three non-collinear points define a plane, it must have at least two lines.
We will use the concept of the non-collinear points.
We could have a line and a point not on that line, two intersecting lines, two parallel lines, or literally three non-collinear points since three non-collinear points define a plane.
For three non-collinear points, use the following formula: If none of the three points are collinear, we can draw three lines, one for each point.
These lines might or might not cross. If two of the three points are collinear, we have a line connecting them and a line connecting the third point. These lines can converge or be parallel once more.