Tuesday, March 11, 2008
Geometry (Class 60)
Announcements
Test Friday. Focus will be on Chapter 8 Lesson 1- Lesson 5.
Lesson Title
Triangles in Right Triangles 2
Overview
In the last class we saw how similar right triangles are hiding inside any right triangle. We also learned how to find the corresponding sides and angles of these triangles and saw that many statements of proportionality between the triangles can be written. In today’s class we build on these ideas and use them to solve some related problems, including a proof of the Pythagorean Theorem.
Textbook Sections
Vocabulary
similar, similarity statement
ratio
proportion
scale factor
statement of proportionality
geometric mean
golden section
golden rectangle
altitude
hypotenuse
right triangle
Key Attitudes
Math is about thinking creatively.
Key Ideas
Inside any right triangle there exists other right triangle which are similar to the original.
Since the right triangles created by constructing an altitude to the hypotenuse are similar, the corresponding sides are proportional
If you are given a geometric mean, you only need two values to solve the proporion.
Key Skills
Creating similar right triangles inside a right triangle.
Solve problems involving similar right triangles formed by the altitude drawn from the hypotenuse of the right triangle
Creating and using geometric means to solve problems.
Turn-In (#59)
Txt. p.522 #16-18, 53-58
Txt. p.801 #1-3
Handouts
Chapter 12- Solid 3 (Right Triangular Prism)
Assignment
§9.1 (Txt. p.531)#11-21, 25-27
Test Corrections
Finish Chapter 8- Lesson 6 through #9b
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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