Do-Now Is enough information given to prove the following triangles congruent? If so, which postulate is being used? Z A D No ASA C B E W X Y B A C AAS F D E

Example #1 – SSS – Postulate Use the SSS Postulate to show the two triangles are congruent. Find the length of each side. AC = 5 BC = 7 AB = MO = 5 NO = 7 MN = ∆ABC  ∆MNO

Remember Mid-Point of a Line Segment Cuts the line segment into two EQUAL (congruent) parts

Example #2 – SAS – Postulate Given: N is the midpoint of LW N is the midpoint of SK Prove: ∆LNS  ∆WNK Statements Reasons 1) N is the midpoint of LW N is the midpoint of SK 1) Given 2) Definition of Midpoint 2) 3) Vertical Angles are congruent 3) ∆LNS  ∆WNK 4) 4) SAS Postulate

Congruent Triangles – 2 Column Proofs B C D E 1 2 Prove ∆AEB = ∆ DEC. Q P S R Prove ∆QPR = ∆ PSR.

A R G D Prove ∆ADR = ∆ DRG. A B C D E Prove ∆ADB = ∆ BCE.

A B C D 1 2 Prove ∆ABC = ∆ ADC. S P T Q Prove ∆SPQ = ∆ TPQ.