 Welcome Geometry Scholars! We're going to start chapter 2 with this unit introducing you to logic. You're going to have to put together logical statements further down the road when we make proofs. And so we're going to give you some logic skills to help you do that accurately. Get out your note sheet and follow along with these instructions. The first vocab word we're going to talk about is conjecture. A conjecture is an educated guess based on the known information. Please copy this definition onto your note sheet. An example of this would be the numbers 5, then negative 10, then 15, then negative 20. What would the next number be in that series? If you had the series 5, negative 10, 15, and negative 20. The next number in that series would be what? The numbers are going up by 5, so 5, 10, 15, 20. The next number would be 25, and it would also be positive. The numbers are alternating between positive and negative. So based on the known information, positive 5, negative 10, positive 15, negative 20. Your educated guess would be positive 25. Inductive reasoning is reasoning that uses a number of specific examples to arrive at a generalization or prediction. Copy this onto your note sheet. An example of that would be I'm walking around downtown Minneapolis on a Sunday afternoon in the fall and I see a lot of people wearing Green Bay Packer jerseys. A logical conclusion would be that the Vikings are playing the Green Bay Packers that Sunday afternoon. A counter example is an example used to show that a given statement is not always true. Copy this into your notes. A situation that is a counter example would be, first, the statement, all freshmen are short. A counter example of all freshmen are short would be to find in your classroom a tall freshman. That person would be a counter example to the statement, all freshmen are short. Because not, all freshmen are short. Before you go on to the next video, please complete numbers 1 through 3 on your note sheet.