- conditional statements
- biconditional statements
- proofs
-theorems
-postulates

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Inverse

Negate the hypothesis & conclusion of a conditional statement

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Contrapositive

Negate the hypothesis & conclusion of the converse of an original statement

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Converse

A conditional statement formed by switching the hypothesis and conclusion

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Biconditional statement

a statement that contains the phrase "if and only if"

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Law of detachment

if p ➡ q is a true conditional statement and p is true, than q is true

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Law of syllogism

if p ➡q and q➡r are true conditional statements then p➡r is true

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Congruent Supplements Theorem

If 2 angles are supplementary to the same angle (or to congruent angles) then they are congruent

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Congruent Complements Theorem

If 2 angles are complementary to the same angle (or to congruent angles) then they are congruent

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Linear Pair Postulate

If 2 angles form a linear pair, then they are supplementary

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Vertical Angles Theorem

Vertical angles are congruent

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Right Angle Congruence Theorem

All right angles are congruent

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Postulate

A statement accepted without a proof

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Theorem

Statement that is proved