110 Geometry Bell Ringer 1 Grab todays materials

1/10 Geometry Bell Ringer 1. Grab today’s materials from front 2. What geometry properties are illustrated in the following diagrams? What is CD? Homework: Finish 3 Proofs! Extra Credit Question!

1/10 Perfection Competition • • • 1 st Period MVP: 2 nd Period MVP: 4 th Period MVP: 7 th Period MVP: 8 th Period MVP: Friday’s Perfection Winner: 7 th Period

Missing Quizzes – Today after school or a zero. • • • 1 st: 2 nd: 4 th: 7 th: 8 th:

1/10 Agenda • I CAN review structure of a two-column proof and prove that two triangles are congruent when given two corresponding parts congruent • 1. Bell Ringer • 2. New Material – Quick Review/ One Example. • 3. Guided Practice – 2 Mr. Fix Its • 4. Independent Practice

Today’s Goal • PROVE two triangles are congruent! • Why do we need to prove things? – Because “it’s obvious!” isn’t a reason why. – Because sometimes things that appear to be true are actually false. – Because it makes you understand WHY things are true! – Tests your knowledge of ALL geometry concepts and connects them all!

Structure of a Two-Column Proof Statements Relationships within the diagrams that are true. Reasons What property/theorem allows you to make this statement?

Steps to Proving 2 Triangles Are Congruent • Step 1: Mark/Use Given Information • Step 2: Use properties, theorems, postulates that you know to get 2 triangles to show a shortcut postulate. • Step 3: Make statement that 2 triangles are congruent by SSS, SAS, ASA or SAA • Step 2 is the CHALLENGE, are you up to it?

Let’s find out… • Given: • Prove:

But what if something else is given… • Given: • Prove:

Mr. Fix-It #1 • Given: • Prove:

Mr. Fix-It #2 • Given: PT = ST = 5 cm • Prove: ΔQPT is congruent to ΔRST

Extra Credit • Do some research tonight and find something that was once believed to be true that is now false. • You must have a unique answer, so “sharing” is a dumb idea.

Independent Practice Rules • You must work on these while we’re in class. • You must ask question when you’re confused. • I will not talk to you unless your hand is raised. If you think you’re waiting too long to talk to me, go on to the next proof, it will be looking for different things. • Your effort is so important this week!

Independent Practice • There are 4 proofs for you to work on for tomorrow. These are meant to challenge you! • What will help? – VOCABULARY SHEETS! – Today’s Notes – Last week’s notes on recognizing shortcuts! – http: //www. chrischilles. wordpress. com if you get stuck, ask questions!