• Line
• Collinear points
• Non-collinear points
• Distance of a point from a line

Line: A line is a geometric figure that consists of an infinite number of points lined up straight that extend in both directions forever.

Collinear points: If three or more points lie on the same line, they are called collinear points.

Non-collinear points: If three or more points don't lie on the same line, they are called Non-collinear points.

Line:

• A line is a geometric figure that consists of an infinite number of points lined up straight that extend in both directions forever.

• A line has no endpoints on either side.

• A line is one-dimensional. That is, a line has length, but no width or height.

• A line is uniquely determined by two points.

• The line passing through the points A and B is denoted by `
  \[\overleftrightarrow{AB}\].

• Sometimes small letters l, m, n, etc. will be used to denote lines.

• One and only one line can be drawn through any two distinct points.

• If three or more points lie on the same line, they are called collinear points.

  Points not on the same line are the non-collinear points.

• An infinite number of lines can be drawn through one point.

• When two or more lines pass through the same point, they are called concurrent lines, and the common point through which they pass is called their point of concurrence.