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Geometry Essentials, Day 4 Today: ο· ο· Name ____________________________ You will learn how to use deductive reasoning to write a two-column proof. At the end of class you will be able to prove statements about segments, angles, and angle pair relationships. You will be able to write a two-column proof to justify your steps in solving an algebraic equation. Postulates: Theorems: Proofs: Points/Lines/Planes Postulates Postulate 1) 2) 3) 4) 5) 6) Illustration Perpendiculars Def. Perpendicular lines planes line and a plane 2π₯ + 5 = 30 − 3π₯ 5π₯ + 5 = 30 5π₯ = 25 π₯=5 c. d. π + π(ππ + π) = ππ Statements Reasons π∠1 = π∠3 π∠1 + π∠2 = π∠2 + π∠3 π∠1 + π∠2 = π∠π·π΅πΆ π∠2 + π∠3 = π∠πΈπ΅π΄ π∠π·π΅πΆ = π∠πΈπ΅π΄ Definition of Congruent Angles – If the measures of two angles are congruent then the angles are congruent π∠1 = π∠3