1. Points, Lines, Planes and Segments
Vocabulary Term
Definition
Name/Drawing/Symbol
Point
Indicates a location; has no size
Named by a capital letter and represented by a dot.
Line
Made up of points, has length only, no thickness or width
Named by 2 points on the line (capital letters), or by a single lower case letter.
Plane
A flat surface that extends without end and has no thickness. Contains infinitely many lines.
Named by a capital letter or by at least 3 points in the plane that do not all lie on the same line
Segment
Part of a line; has 2 endpoints and all the points between them
Named by its 2 endpoints (order doesn’t matter)
Ray
Part of a line which has one endpoint; extends infinitely in one direction
Named by its endpoint and one point it goes through. Name the endpoint first.

2. Constructing Congruent Line Segments
In order to draw a line segment that is congruent to a given line segment, we are going to use the GeoTool compass.
1) Place the red circle over one end of the line segment, with the endpoint in the middle of the circle.
2) Slide the rectangular piece until it is on the other endpoint.
Turn the red knob to tighten this piece in place.
3) Using the straight edge of the GeoTool, draw a reference line (unless one has been provided for you).
4) Place the red circle over one of the endpoints of your reference line (center it).
5) Place your pencil into the hole in the rectangular piece and draw a mark that crosses the reference line.
6) The line segment between your endpoint and intersecting mark will be congruent to the given line segment.