Difference between revisions of "Points, Lines, Segments, Angles etc."
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Ouside source: [[http://www.mathleague.com/help/geometry/basicterms.
Ouside source: [[http://www.mathleague.com/help/geometry/basicterms.| Math League: Basic Terms]] Click on the link and look at the examples.
Revision as of 16:08, 4 January 2009
Points and Lines
A point is a specific location in space. A point is drawn as a dot. Often we label a point with some letter. We would say "Point A" for instance.
Above you see three points labeled A, B and C.
Lines are something you have seen in Algebra. Straight lines go on infinitely far in both directions. Closely related to the line are rays and line segments.
A ray is what we can think of as "half a line". A ray starts at a given point and then goes of to infinity in one direction.
A line segment is just a small part of a line. It starts at one point and ends at another.
In the picture above we see the difference between a line, a ray and a segment. The line is the figure at the top. As we can see it goes on for ever. The figure in the middle is a ray. It starts at a point and then moves off to the top-right. The line segment is all the way at the bottom.
Example showing several line segments and their labels
We will be using line segments a lot in later sections. We will label segments by recording the endpoints. For example:
In this diagram we see several line segments:
- Segment AP is the line segment connecting A and P. Note that we can also call this segment PA.
- Segment AB (or BA if you like) runs vertically.
- Segment BP is the third segment shown.
AM, MB and MP are also segments. There is also a line in this picture. It is labeled r.
Do the following Lines and Line Segment Worksheet to check that you have remembered what lines and segments are.
Ouside source: [| Math League: Basic Terms] Click on the link and look at the examples.