Mathematical Justifications Valid Mathematical Justifications Are used to support conclusions in a proof or mathematical argument. They can be… Definitions Postulates Properties Theorems
“Definition of _____________________________” Congruent: ↔ = Bisect: bisect ↔ Midpoint: midpoint ↔ segments Supplementary: supplementary ↔ sum 180 Right angle: rt ↔ 90
Postulates we know… Segment Addition Postulate Angle Addition Postulate A B C D A C B
Properties…
Linear pair supplementary THEN IF Linear pair supplementary 1 2 supplementary Vertical angles congruent (Vertical s ) 1 2 Right angles congruent (rt. s ) 1 2
Reflexive Property of = Symmetric Property of =
Definition of Supplementary Angle Addition Postulate
↔ = Linear Pair → supplementary
Addition Property of = Bisect ↔ Vertical s →
Solve for x. 1 2 3 4
1 2 3 4