Ray (Coordinate Geometry)

Definition: A line which starts at a point with given coordinates, and goes off in a particular direction to infinity, possibly through a second point.
Try this Adjust the ray below by dragging an orange dot and see how the ray AB behaves. You can also drag the origin point at (0,0).

A ray is a line that starts at a given point and goes off for ever in some direction. It may pass through another point as it does so. This is the same as the definition of a Ray in ordinary plane geometry, the only difference being that we know the coordinates of the points involved. The naming conventions are also the same.

## Things to try

1. In the above diagram, press reset. The ray AB has an endpoint A at (53,7) and passes through point B at (53,20) on its way to infinity.
2. Drag A, B or the origin point and construct various other rays to get a feel for the concept.

## Limitations

In the interest of clarity in the applet above, the coordinates are rounded off to integers and the lengths rounded to one decimal place. This can cause calculatioons to be slightly off.

For more see Teaching Notes

## Other Coordinate Geometry entries

COMMON CORE

Math Open Reference now has a Common Core alignment.

See which resources are available on this site for each element of the Common Core standards.

Check it out