Friday, February 22, 2008
Geometry (Class 54)
Lesson Title
A Triangle in a Triangle 1
Overview
The warm-up for today’s class focuses on proving triangles similar using the SAS similarity theorem. The lesson for the class continues this focus on similarity to examine relationships created by having a triangle in a triangle.
Textbook Sections
§8.6 (Txt. p. 498) Proportions and Similar Triangles
Vocabulary
similar, similarity
similarity statement
scale factor
statement of proportionality
Key Attitudes
Math is about thinking creatively.
Key Ideas
Triangles are similar if and only if all of the corresponding sides of the triangles are in equal ratios. (Definition of Similarity)
Triangles are similar if and only if two pairs of angles are congruent. (AA Similarity Theorem and Converse of AA Similarity Theorem)
Triangles are similar if and only if a pair of angles are congruent and both pairs of adjacent sides are in the same ratio (SAS Similarity Thm. and Converse of SAS Similarity Theorem)
Key Skills
Determine if two triangles are similar using shortcuts (AA, SAS)
Prove triangles similar.
Turn-In (#53)
Chapter 8- Lesson 2: Proofs
§8.5 (Txt. p.492) #6-12, 19-25
Handouts
Chapter 8- Lesson 2: Proving Triangles Similar using SAS
Chapter 8- Lesson 3: A Triangle in a Triangle
Assignment
Chapter 8- Lesson 2: Proving Triangles Similar using SAS
§8.5 (Txt. p.492) #13, 14, 26-28, 32, 33
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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