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2/8 Geometry Bell Ringer 1. Mr. Chrischilles made chili for his Super Bowl Party. The recipe called for 2 cans of chili beans in order to serve 5 people. If Mr. Chrischilles needed to serve 20 people? (Set up proportion to solve) 2. What were the 4 Congruent Triangle Postulates (shortcuts) that we used to prove triangles were congruent? Homework: Identifying Similar Triangles Indep. Practice 2/8 News and Notes • • • • Perfection Award: 1st Period HW Checked? Tardy Policy Reminder Remember, Quiz Friday! Perfection Competition Daily Results 2 2 1.5 1 1 1 0.5 0 1st 2nd 4th 0 0 7th 8th Today = A College Test • Today is going to be different. • Quick story about Prof. Chamlee-Wright • 1. We will have a discussion for 10-15 minutes I will pose questions, you will offer your thoughts. • 2. Eventually you won’t need to raise your hands, but today you will as we adapt. • 3. Constructive Criticism: “I disagree, it seems to me that is true.” • 4. EVERY COMMENT is VALUABLE • 5. Today I’ll write important stuff on board, eventually I won’t need to do this. You’ll write in your notes and you’ll be able to use your notes on the 2 question quiz after class. Remember our new rules: • 1. Give Respect, Get Respect – Constructive Criticism • 2. Be on time and start bell ringer right away • 3. Prepared means binder, homework, pen/pencil, and handouts for today are ready. • 4. “I Can” not “I Can’t” • 5. Quiet when others are talking Questions driving conversation: • From the bell ringer, what were our 4 postulates/shortcuts from Congruent Triangles? • What’s the difference between congruent triangles and similar triangles? • Are congruent triangles still similar? • What’d we say about AAA for congruent triangles? • Do we have to show all 3 angles, or can we make similarity conclusion with fewer, why? • AA Similarity Postulate: • What is then guaranteed to be true about sides? More Questions • So we’ve used the angle portion of our definition, what’s the other part of the definition of similar triangles? • If you knew that the three sides were proportional, what would be true about the angles? Why? • SSS Postulate: • Example. More • What other congruent triangle postulates were there besides SSS? • Why do we not need to talk about SAA or ASA? • SAS Postulate Example • SSA still doesn’t work, why? One Example, One Non-Example 1. Shortcut SAS 2. Does it work to prove? YES 3. Do proportions work? 2 6 ? 4 12 24 = 24 One Example, One Non-Example 1. Shortcut SSS 2. Does it work to prove? YES 3. Do proportions work? 2 3 ? 6 3 6 = 18 Independent Practice • 5 examples, one non-example • 3 steps: – 1. Identify shortcut Put in box – 2. Check proportions if sides involved – 3. If similar, state similar triangles. 2 Question Quiz