Opposite Rays
From Latin: oppositus - "set against"
Definition: Two rays with a common endpoint that point in opposite directions and form a straight line.
Try this Adjust the rays below by dragging any orange dot. The two rays (blue and red) will only be opposite when they point in exactly opposite directions.

Opposite rays are two rays that both start from a common point and go off in exactly opposite directions. Because of this the two rays (QA and QB in the figure above) form a single straight line through the common endpoint Q.

When the two rays are opposite, the points A,Q and B are collinear.

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