1. 1-2 Points, Lines, and Planes
L.E.Q. How do you explain the basic terns and postulates of geometry?

2. What is a point? A location. Without size. Represented by a dot.
Named by a capital letter.
“Point A”

3. What is space?
The set of all points.

4. What is a line?
A series of points that extends in two opposite directions without end.
You can name a line by any two points on the line with a little line symbol above them. A B

5. What does it mean to say collinear?
Points that lie on the same line.
We would say that points A, B, C, and D are collinear.

6. EXAMPLE 1: Identifying Collinear Points.
Are points U, V, and P collinear? If they are, what line do they fall on?
Name another set of collinear points.

7. What is a plane?
It is like a flat surface that extends infinitely along its length and width.
It has no thickness.

8. What does it mean to say that figures are coplanar?
Points and lines in the same plane.
Points G and O are coplanar.

9. EXAMPLE 2: Naming a Plane.
Name the plane represented by the front of the cube.
Name the top plane.
Name the left plane.
Name a diagonal plane.

10. What is a postulate/axiom?
An accepted statement of fact.

11. Postulate 1-1
Through any 2 points there is exactly ______ line.

12. Postulate 1-2
If 2 lines intersect, then they intersect in exactly ______ __________.

13. Postulate 1-3
If two planes intersect, then they intersect in exactly ______ _________.

14. Postulate 1-4
Through any three noncollinear points there is exacly ______ _________.

15. Closure:
Explain how a postulate and a conjecture are different.

16. Homework:
Pgs 13 – 15 #s 2 – 66 even.