Monday, October 20, 2008
Geometry (Class 19)
Lesson Title
Missing Angle Puzzles (1)
Overview
The warm-up for today, Figure It Out! (3), continues working with sum of the interior angles of polygons. Students also work another model drawing problem, Distance and Midpoints (5), concerning (Surprise!) distance and midpoints.
The lesson for the day moves us into the next chapter. This chapter will be primarily concerned with the logical structures that underlie formal mathematical proofs. In this first lesson students will be working on “Missing Angle Puzzles” as the context for developing the ability to explicitly state reasoning that compels them to draw a conclusion.
Textbook Sections
N/A
Vocabulary
acute angle
obtuse angle
right angle
straight angle
supplementary angles
complementary angles
adjacent angles
bisect
deduce, deduction
counter example
Key Attitudes
Math is about thinking creatively.
Key Ideas
A proof is the sequence of reasons which, when put together, compels you to believe something.
Key Skills
I can deduce the measure of angles.
I can state the steps I use to come to a conclusion.
I can record the steps I used to come to a conclusion in written form.
I can use the concept of a counter example to show that something is not necessarily true.
Turn-In (#18)
Txt. p.29 #26-43
Txt. p.32 65-67, 77-79
Handouts
Chapter 2- Lesson 1: Missing Angle Puzzles
Assignment
Chapter 1- Lesson 3
Txt. p.39 #17-20, 25-27, 37-39, 44-46
Disclaimer- The assignment as stated in class is the official assignment. Every effort is made to keep this posting accurate, but you should refer to what was stated in class as the final word.
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