Geometry Unit 2 Vocabulary

Front 1

inductive reasoning

Back 1

uses patterns to make conjectures

Front 2

conjecture

Back 2

an unproven statement based on observations

Front 3

counterexample

Back 3

a specific example that proves a conjecture false

Front 4

deductive reasoning

Back 4

uses facts and definitions to make a conclusion

Front 5

conditional statement

Back 5

a logical statement that has two parts: a hypothesis and a conclusion

Front 6

hypothesis

Back 6

the "if" part in a conditional statement

Front 7

conclusion

Back 7

the "then" part a conditional statement

Front 8

negation

Back 8

has the exact opposite meaning of the original statement

Front 9

original conditional statement

Back 9

if-then statement

Front 10

contrapositive

Back 10

switch and negate hypothesis and conclusion

Front 11

the original conditional statement and _____ _____________ have the same truth value

Back 11

the contrapositive

Front 12

converse

Back 12

switch hypothesis and conclusion

Front 13

inverse

Back 13

negates hypothesis and conclusion

Front 14

the inverse and ___ _____________ have the same truth value

Back 14

the converse

Front 15

biconditional statement

Back 15

a statement that contains the phrase "if and only if" (IFF). Can be used when a conditional statement and its converse are both true.

Front 16

law of detachment

Back 16

if the hypothesis of a true conditional statement is true, then the conclusion is also true.

Front 17

law of syllogism

Back 17

if hypothesis p, then conclusion q. If hypothesis q, then conclusion r. If hypothesis p, then conclusion r.

**Always has 3 if-then statements**

Front 18

postulates/axions

Back 18

rules that are accepted without proof

Front 19

theorems

Back 19

rules that are proved

Front 20

If *two points*, then *line*

Back 20

Through any two points there exits exactly one line

Front 21

If *line*, then *two points on line*

Back 21

A line contains at least two points

Front 22

If *two lines intersecting*, then *two lines intersecting at a point*

Back 22

If two lines intersect, then their intersection is exactly one point

Front 23

If *three noncollinear points*, then *plane*

Back 23

Through any three noncollinear points there exists exactly one plane

Front 24

If *empty plane*, then *plane with three noncollinear points*

Back 24

A plane contains at least three noncollinear points

Front 25

If *plane with two points*, then *plane with line through two points*

Back 25

If two points lie in the same plane, then the line containing them also lies in the plane.

Front 26

If *two planes intersecting*, then *two planes intersecting at a line*

Back 26

If two planes intersect, thne their intersection is a line

Front 27

Perpendicular lines and planes rule

Back 27

A line is a line perpendicular to a plane IFF the line intersects the plane in a point and is perpendicular to every line in the plane that intersects at that point. (showed by a right angle)