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Proving Triangles are Congruent: SSS and SAS. Chapter 4.3. Objectives/Assignment. Prove that triangles are congruent using the SSS and SAS congruence postulate Use congruence postulates in real life problems Assignment: 2-28 even, 44-46 all. Goal 1: SSS & SAS Congruence Postulates.
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Proving Triangles are Congruent:SSS and SAS Chapter 4.3
Objectives/Assignment • Prove that triangles are congruent using the SSS and SAS congruence postulate • Use congruence postulates in real life problems • Assignment: 2-28 even, 44-46 all
Goal 1: SSS & SAS Congruence Postulates Postulate 19: (SSS) Side-Side-Side Congruence Postulate • If three sides of one triangle are congruent to three sides of a second triangle, then the two triangles are congruent. Side BCEF, and
Postulate 20: (SAS) Side-Angle-Side Congruence Postulate • If two sides and the included angle of one triangle are congruent to two sides and the included of a second triangle, then the two triangles are congruent. If Side QSYZ, Side PSXZ, PQS XYZ
Goal 2: Modeling a Real Life Situation Example 3: Choosing Which Congruence Postulate to Use Paragraph Proof The marks on the diagram show that PQ PS and QR SR. By the Reflexive Property of Congruence, RP RP. Because the sides of ΔPQR are congruent to the corresponding sides of ΔPSR, you can use the SSS Congruence Postulate to prove that the triangle are congruent.
Example 6: Congruent Triangles in a Coordinate Plane • Use the SSS Congruence Postulate to show that ABC FGH. AC = FH = 3 AB = FG = 5 AB FG **Use the Distance Formula to find the lengths BC and GH** H(6,5) A(-7,5) C(-4,5) Who remembers the distance formula? F(6,2) G(1,2) B(-7,0) BC = GH = √34 All sides congruent