Question 885887: Can you helo me with this probkem. Points a,b,c,and d are collinear. In how many ways can the line be named using only these points? Points a,b,c,d, and e are coplanar and no three are collinear. In how many ways can the plane be named using only these points?
Answer by DrBeeee(684)   (Show Source):
You can put this solution on YOUR website! Problem 1;
We can select two points (to define a line) from the four points 4*3 or 12 different ways. However if we assume that order does not matter, that is line ab is the same as line ba, this number is divided by 2! or 2.
Answer: We can name the line six ways.
Problem 2;
We can select three points(to define a plane)from the five points 5*4*3 or 60 different ways. However if we assume that order does not matter, that is plane abc is the same plane acb, bac, bca, cab or cba, this number is divided by 3! or 6.
Answer: We can name the plane ten ways.
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