Rays and Angles

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?

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/