Wednesday, March 05, 2008
Geometry (Class 58)
Chapter 8- Lesson 5: Donald Duck in Mathmagic Land
Announcements
Test Friday. Focus will be on Chapter 8 Lesson 1- Lesson 5.
Lesson Title
The Golden Rectangle
Overview
In today’s class we develop the concept of a “geometric mean” and how this relates to the golden section and to golden rectangles. As time permits we will also begin work examining proportional relationships inherent in right triangles.
Textbook Sections
§8.2 (Txt. p.465) Problems Solving in Geometry with Proportions
§9.1 (Txt. .527) Similar Right Triangles
Vocabulary
similar, similarity
similarity statement
scale factor
statement of proportionality
geometric mean
golden section
golden rectangle
Key Attitudes
Math is about thinking creatively.
Key Ideas
A “golden section” is created when a line segment of length a is divided into two segments of length b and c such that b/a=c/b.
The golden section gives rise to a quadratic equation.
Quadratic equations can be solved by using the quadratic formula
Key Skills
Create a golden rectangle.
Simplify an algebraic proportion.
Solve a quadratic equation using the quadratic formula.
Turn-In (#57)
Complete Warm-Up
§8.6 (Txt. p.502) #25-28, 39a-c
Txt. p.517 #8-17
Handouts
Chapter 8-Lesson 5: The Golden Rectangle and the Geometric Mean
Chapter 8- Lesson 6: Seeing Similarities
Assignment
Txt. p.519 #1-9, 10-15, 17
Txt. p.522 #1-3, 13-15
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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