Example: Lines through Non-collinear
Points
Consider points A, B, C, D, and E no three of which are collinear. How
many lines can be drawn through these points such that each line
contains two of the points?
A
B
C
DE
Example: Lines through Non-collinear
Points
Consider points A, B, C, D, and E no three of which are collinear. How
many lines can be drawn through these points such that each line
contains two of the points?
A
B
C
DE
There are 4 lines
through point A and
one other point
4
Example: Lines through Non-collinear
Points
Consider points A, B, C, D, and E no three of which are collinear. How
many lines can be drawn through these points such that each line
contains two of the points?
A
B
C
DE
There are 3
additional lines
through point B and
one additional point
4 + 3
Example: Lines through Non-collinear
Points
Consider points A, B, C, D, and E no three of which are collinear. How
many lines can be drawn through these points such that each line
contains two of the points?
A
B
C
DE
There are 2
additional lines
through point C and
one additional point
4 + 3 + 2
Example: Lines through Non-collinear
Points
Consider points A, B, C, D, and E no three of which are collinear. How
many lines can be drawn through these points such that each line
contains two of the points?
A
B
C
DE
There is 1 additional
line through point C
and one additional
point
4 + 3 + 2 + 1
Example: Lines through Non-collinear
Points
Consider points A, B, C, D, and E no three of which are collinear. How
many lines can be drawn through these points such that each line
contains two of the points?
A
B
C
DE
4 + 3 + 2 + 1 = 10
10 lines

Example Lines through Noncollinear Points

  • 1.
    Example: Lines throughNon-collinear Points Consider points A, B, C, D, and E no three of which are collinear. How many lines can be drawn through these points such that each line contains two of the points? A B C DE
  • 2.
    Example: Lines throughNon-collinear Points Consider points A, B, C, D, and E no three of which are collinear. How many lines can be drawn through these points such that each line contains two of the points? A B C DE There are 4 lines through point A and one other point 4
  • 3.
    Example: Lines throughNon-collinear Points Consider points A, B, C, D, and E no three of which are collinear. How many lines can be drawn through these points such that each line contains two of the points? A B C DE There are 3 additional lines through point B and one additional point 4 + 3
  • 4.
    Example: Lines throughNon-collinear Points Consider points A, B, C, D, and E no three of which are collinear. How many lines can be drawn through these points such that each line contains two of the points? A B C DE There are 2 additional lines through point C and one additional point 4 + 3 + 2
  • 5.
    Example: Lines throughNon-collinear Points Consider points A, B, C, D, and E no three of which are collinear. How many lines can be drawn through these points such that each line contains two of the points? A B C DE There is 1 additional line through point C and one additional point 4 + 3 + 2 + 1
  • 6.
    Example: Lines throughNon-collinear Points Consider points A, B, C, D, and E no three of which are collinear. How many lines can be drawn through these points such that each line contains two of the points? A B C DE 4 + 3 + 2 + 1 = 10 10 lines