In elementary school you learn a lot of introductory geometric vocabulary. Now, you will be doing a LOT more with what you've learned. Let's do some review now, shall we? The Basic Building Blocks: Undefined Terms In geometry, the most basic figures are undefined; they cannot be defined by using a particular figure or shape. There are three of these terms: point, line, and plane. 

point – names a specific location and has no size. It is represented by a dot.
line – a straight path that extends forever and has no thickness. It is represented by a line with an arrow at each end.
plane – a flat surface that extends forever in all directions that has no thickness. It is represented by a script (italicized) capital letter.
collinear – points that lie on the same line coplanar – points that lie in the same plane 

Defined Terms Now, we can look at terms that are defined. These are probably what you remember from elementary school. 

segment (or line segment) – names a part of a line consisting of two points and all the points between. It is named by two endpoints.
endpoint – a point at one end of a segment or the starting point of a ray. It is represented by a capital letter.
ray – a part of a line that starts at an endpoint and extends forever in one direction as indicated by an arrow.
opposite rays – two rays that share a common endpoint and form a line
angle – a figure formed by two rays with a common endpoint called a vertex.


©2016 Sherry Skipper Spurgeon for Geometry Bugs Me All Rights Reserved 
