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axiom

a statement that describes a fundamental relationship between the basic terms of geometry

biconditional

the conjunction of a conditional statement and its converse

compound statement

a statement formed by joining two ore more statements

conclusion

the phrase that immediately follows the word then

conditional statement

a statement that can be written in if-then form

conjecture

an educated guess based on known information

conjunction

a compound statement formed by joining two ore more statements within the word and.

contrapositive

the statement formed by negating both the hypothesis and conclusion of the converse of a conditional statement

converse

the statement formed by exchanging the hypothesis and conclusion of a conditional statement

counterexample

an example used to show that the given statement is not always true

deductive argument

a proof formed by a group of algebraic steps used to solve a problem

deductive reasoning

a system of reasoning that uses facts, rules, definitions, or properties to reach logical conclusions

disjunction

a compound statement formed by joining two or more statements with the word or

formal proof

statements and reasons organized in two columns

hypothesis

the phrase immediately following the word if

if-then statement

written in the form if p, then q.

inductive reasoning

uses a number of specific examples to arrive at a plausible generalization

informal proof

you write a paragraph to explain why a conjecture for a given situation is true

inverse

negating both the hypothesis and conclusion of the conditional

Law of Detachment

a form of deductive reasoning that is used to draw conclusions from true conditional statements

Law of Syllogism

similar to the transitive property of equality

logically equivalent

statements with the same truth values

negation

has the opposite meaning as well as an opposite truth value

paragraph proof

write a paragraph to explain why a conjecture for a given situation is true

postulate

statement that describes a fundamental relationship between the basic terms of geometry

proof

a logical argument in which each statement you make is supported by a statement that is accepted as true

related conditionals

other statements based on a given conditional statement

statement

any sentence that is either true or false but not both

theorem

a statement or conjecture that can be proven true by undefined terms, definitions, and postulates

truth table

a table used as a convenient method for organizing the truth values of statements

truth value

the truth of falsity of a statement

two-column proof

containing statements and reasons organized in two columns.