Undefined Terms and Definitions

1. Undefined Terms and Definitions

2. Undefined Terms Point • simply a location • represented by a dot • named with a capital letter • no shape • no size

3. Undefined Terms (cont.) Line • made up of points • no thickness or width • drawn with an arrowhead at each end • named by the letters representing two points on the line or by a lowercase script letter • has symbol in label above two letters SL or LS

4. Undefined Terms (cont.) Plane • flat surface made up of points • no depth • extends infinitely in all directions • drawn as a shaded, slanted four-sided figure • named by a capital script letter or by the letters naming three points in the plane that are not on the same line

5. Definitions (cont.) Collinear - points on the same line Coplanar - points that lie on the same plane Intersection – The point(s) in common among figures Space – A boundless three-dimensional set of all points.Space can contain lines and planes. Locus – A set of points that all satisfy a particular condition.

6. Use the figure to name each of the following. a. a line containing point X Answer: line c, b. a plane containing point Z Example 1-1d Answer: plane P, plane XYZ, plane ZYX, plane YZX, plane XZY, plane ZXY, plane YXZ

7. VISUALIZATION Name the geometric shape modeled by each object. a. a colored dot on a map used to mark the location of a city b. the ceiling of your classroom Example 1-2d Answer: point Answer: plane

8. Example 1-4e a. How many planes appear in this figure? Answer: two

9. Example 1-4f b. Name three points that are collinear. Sample answer:A, X, and Z

10. Example 1-4g c. Are points X, O, and R coplanar? Explain. Answer: Points X, O, and R all lie in plane T, so they are coplanar.

11. d. At what point do and intersect? Example 1-4h Answer:R