2.6 Geometric Proof

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## 2.6 Geometric Proof

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**2.6 Geometric Proof**Objectives: Write two-column proofs. Prove geometric theorems by using deductive reasoning. Vocabulary: Theorem – a statement that can be proven true. Two-column proof – format for proofs where the statements are listed on the left and the reasons are listed on the right.**Definitions**• Postulates • Properties • Theorems Conclusion Hypothesis 2.6 Geometric Proof When writing a proof, it is important to justify each logical step with a reason. You can use symbols and abbreviations, but they must be clear enough so that anyone who reads your proof will understand them.**2.6 Writing a Proof**A geometric proof begins with Given and Prove statements, which restate the hypothesis and conclusion of the conjecture. In a two-column proof, you list the steps of the proof in the left column. You write the matching reason for each step in the right column. Before you start writing a proof, you should plan out your logic. Sometimes you will be given a plan for a more challenging proof. This plan will detail the major steps of the proof for you.**Helpful Hint**If a diagram for a proof is not provided, draw your own and mark the given information on it. But do not mark the information in the Prove statement on it. 2.6 Tips**2.6 Practice**Write the letter of the correct justification next to each step. (Use one of them twice) B A B C**2.6 Proof**Statements 1. 2. 3. 4. Reasons 1. Given 2. 3. Substitution Prop. of = 4.**2.6 ProofMark the diagram and answer the questions about the**proof on the following slide. Statements Reasons**2.6 Proof Questions**• What was the given information? • What should be marked in the diagram? • What was the conjecture to be proved? • What titles should be put above the two columns?**2.6 Video explanation for Proofs**Copy the link below and paste it into the address bar to visit the website. Watch the video explanations for the sample proof problems. Link to Holt textbook video lessons: http://my.hrw.com/math06_07/nsmedia/homework_help/geo/geo_ch02_06_homeworkhelp.html