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### Rays and Angles

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Date: 11/24/97 at 01:11:49
From: Kerry Dennis
Subject: Rays and Angles

I do not understand rays. Do they have a arrow on both ends or is that
an angle? Can you give me the defination of a ray?
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Date: 11/24/97 at 09:07:38
From: Doctor Jerry
Subject: Re: Rays and Angles

Hi Kerry,

Although there is no universally accepted definition of a ray, the
most common definition is a line starting at some point of the plane
or space and proceeding outwards. For example, the set of all real
numbers larger than or equal to 5 is a ray. In the plane, the set of
all points (x,x), where x >= 3 is a ray starting at (3,3) and going
outwards "to infinity."

Roughly speaking, a ray is "one-half" of a line.

-Doctor Jerry,  The Math Forum
Check out our web site!  http://mathforum.org/dr.math/
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Associated Topics:
Elementary Definitions
Elementary Geometry
Elementary Two-Dimensional Geometry
Middle School Definitions
Middle School Geometry
Middle School Two-Dimensional Geometry

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