Thursday, March 19, 2009
Geometry (Class 62)
Lesson Title
Similar Triangles (5)
Overview
The opener today examines squaring binomials and recognizing the pattern that this generates. This provides the foundation for solving perfect square trinomials as well as for developing the technique of completing the square-- all very important algebra for next year!
The lesson for the day continues to focus on similar triangles, writing and using proportions, and then proving triangles similar.
Textbook Sections
§8.4 (Txt. p. 480) Similar Triangles
Vocabulary
construction
straight edge
arc
radius
center
diameter
adjacent
opposite
included
non-included
SSS
ASA
SAS
AAS
HL
Key Attitudes
Math is about building up understanding one idea at a time.
Key Ideas
Triangles can be constructed out of various combinations of angles and sides.
Only some combinations of angles and sides guarantee that all triangle created with this combination will be congruent-- the same size and the same shape. Other combinations only guarantee triangles which are the same shape, and some combinations guarantee nothing at all!
Triangles which are the same shape always have some key attributes.
Squaring binomials creates a pattern which can be used to solve certain types of quadratic equations.
Key Skills
I can identify key angle and side combinations which force triangles to be congruent.
I can identify and sequence the reasons which establish triangle congruence.
I can use congruent triangles to prove other facts.
I can use a straight edge and compass to construct geometric shapes.
I can square a binomial by inspections.
I can recognize a perfect square trinomial.
I can factor a perfect square trinomial by inspection quickly.
Turn-In (#61)
Finish 8.21 and 8.22 Worksheets
Test Corrections
Handouts
Chapter 8 Lesson 2 Proving Triangles Similar
Assignment
Txt. p.483 #9-20
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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