Geometry Chapter 3 Flashcards
(28 cards)
Space
Space is the set of all points
Collinear
A set of points is collinear if there is line which contains all the points of the set
Coplanar
A set of points is coplanar if there is a plane which contains all of a set
Postulate 4
The Line Postulate
State the Line Postulate
For every two different points there is exactly one line that contains both points
Theorem 3-1
If two different lines intersect, their intersection contains only one point
Exactly one? Only One?
- 1 or 0
Postulate 5
The Plane Space Postulate
State the Plane Space Postulate
A) Every plane contains at least 3 different non-collinear points
B) Space contains at least 4 different non-coplanar points
Postulate 6
The Flat Plane Postulate
State the Flat Plane Postulate
If 2 points of a line lie in a plane, then the line lies in the same plane
Theorem 3-2
If a line intersects a plane not containing it, then their intersection contains only one point
Postulate 7
The Plane Postulate
State the Plane Postulate
Any three points lie in at least one plane, and any three non-collinear points lie in exactly one plane
Theorem 3-3
Given a line and a point not on the line, there is exactly one plane containing both
Theorem 3-4
Given two intersecting lines, there is exactly one plane containing both
Postulate 8
Intersection of Planes Postulate
State the Intersection of Planes Postulate
If two different planes intersect, then their intersection is a line
Convex
A set M is called convex if for every two points P and Q of the set, the entire segment (line on top PQ) lies in M
Postulate 9
The Plane Separation Postulate
State the Plane Separation Postulate
Given a line and a plane containing it. The points of the plane that do not lie on the line form two sets such that
1) each of the sets is convex, and
2) if P is in one of the sets and Q is in the other, then the segment (line PQ) intersects the line
State the Plane Separation Postulate
Given a line and a plane containing it. The points of the plane that do not lie on the line form two sets such that
1) each of the sets is convex, and
2) if P is in one of the sets and Q is in the other, then the segment (line PQ) intersects the line
Half planes pt 1
Given a line L and a plane E containing it, the two sets described in the Plane Separation Postulate are called half planes or sides of L, and L is called the edge of each of them.
Half planes pt2
If P lies in one of the half planes and Q lies in the other, then we say that P and Q lie on opposite sides of L