# Proofs

## 21 terms

### Point

Has no size, no width, named by a capital letter
Represented by a dot, all geometric figures consist of points

### Line

extends forever has no thinkness

### Plane

extends in all directions without ending, has no edges, drawn as a four-sided Figure

### Space

is the set of all points

### Collinear points

points are points all in one line

### Coplaner

Points all in one plane

### Midpoint of a segement

a point that divides the segment into 2 congrunt segments

2 angles in plane with common vertex and common side, no more then 1 common interior point

### Linear Pair Postulate

Angles that add up to 180

If B is between A and C, then AB+BC=AC
Segments that have equal kenghts

### Postulate

(logic) a proposition that is accepted as true in order to provide a basis for logical reasoning(accepted without proof)

### Theorems

statements that can be proven/ are proved

### Substitution Property

If a = b, then either a or b may be substituted for the other in any equation

### Division Property

if a=b and c≠0, then a/c=b/c

### Multiplication Property

if a=b, then ac=bc

### Angle Bisector Theorem

If a point is on the bisector of an angle, then it is equidistant from the two sides of the angle, If ray BX is the bisector of angle ABC, then angle ABX = 1/2angleABC and angle XBC = 1/2 angle ABC

two or more adjacent angles can be added together to create a single larger angle, If ray BC is in the interior of < ABD, the <1 + <2 = < ABD

### reflective property

a = a, when the same number is equal exacly. 8=8, AB=AB

### Transitive Property

If a=b and b=c, then a=c(Dominoes) , If one quantity equals a second quantity, and the second quantity equals a third quantity, then the first quantity equals the third quantity

### Symmetric property

If a=b, then b=a, If one quantity equals a second quantity, then the second quantity equals the first

a(b+c)=ab+ac