Question 1107068: How many different rays can be named using three collinear points P,Q and R? 1 ,2,3 or 4?
Found 2 solutions by stanbon, ikleyn:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! How many different rays can be named using three collinear points P,Q and R? 1 ,2,3 or 4?
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2 points determine a ray.
# of pairs of points = 4C2 = (4*3)/(1*2) = 6 rays
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Cheers,
Stan H.
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Answer by ikleyn(52800)  (Show Source):
You can put this solution on YOUR website! .
Two points (each pair of points) determines TWO rays with the opposite directions.
Depending on which of the two points is its BEGINNING point.
So, we have ordered pairs of points.
Having three points, you may form 3*2 ordered pairs and hence, 6 different rays.
The solution by other tutor is irrelevant.
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