HolcombMath

Wednesday, February 20, 2008

Geometry (Class 53)

Lesson Title
Shortcuts to Similarity- Proofs

Overview
In today’s class our warm-up again focuses on editing and scoring a proof while the in the lesson we pin down the shortcuts to similarity and then use these shortcuts to determine if 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 using shortcuts (AA, SAS)
Prove triangles similar.
Turn-In (#52)
§8.4 (Txt. p.483) #9-26, 29, 30

Handouts
Chapter 8- Lesson 2: Shortcuts to Similarity
Chapter 8- Lesson 3: A Triangle in a Triangle

Assignment
Chapter 8- Lesson 2: Proofs
§8.5 (Txt. p.492) #6-12, 19-25
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.