2.6 Proofs

HW pg. 116 #3­12, 16­18, 29

September 15, 2014

2.6 Prove Statements about Segments & Angles

Proof: logical argument that shows a statement is True.

2‐column proof : numbered statements and corresponding reasons that show an argument in logical order

Example 1

2.6 Proofs

HW pg. 116 #3­12, 16­18, 29

September 15, 2014

Writing a 2‐column proof• Organize reasoning by drawing the diagram• Make 1 statement @ a time.• Start with the given• End with the conclusion(prove part)

Example 1

2.6 Proofs

HW pg. 116 #3­12, 16­18, 29

September 15, 2014

Theorem: statement that can be proven

Theorem 2.1 : Congruence of Segments

Reflexive: AB ≅ AB

Symmetric: If AB ≅ CD, then CD ≅ AB

Transitive: If AB ≅ CD & CD ≅ EF, then AB ≅ EF

Theorem 2.2 : Congruence of AnglesReflexive: <A ≅ <A

Symmetric: If <A ≅ <B, then <B ≅ <A

Transitive: If <A ≅ <B & <B ≅ <C, then <A ≅ <C

Example 2

2.6 Proofs

HW pg. 116 #3­12, 16­18, 29

September 15, 2014

Example 3

2.6 Proofs

HW pg. 116 #3­12, 16­18, 29

September 15, 2014

2.6 Proofs

HW pg. 116 #3­12, 16­18, 29

September 15, 2014

HW pg. 116 #3‐12, 16‐18, 29