Friday, February 15, 2008
Geometry (Class 52)
Lesson Title
Shortcuts to Similarity
Overview
In today’s class our warm-up focuses on the midsegment of a trapezoid. while the lesson for the day focuses on shortcuts for proving that two triangles are similar.
Textbook Sections
§8.5 (Txt. p.488) Proving Triangles are Similar
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.
Write similarity statements.
Write statements of proportionality.
Find missing side lengths or angle measures of similar triangles.
Turn-In (#51)
§6.7 (Txt. p.376) 14-18, 35-38, 41, 42, 50, 51
Handouts
Chapter 6- Lesson 5: Midsegments of a Trapezoid
Chapter 8- Lesson 2: Shortcuts to Similarity
Assignment
§8.4 (Txt. p.483) #9-26, 29, 30
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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