Thursday, March 05, 2009
Geometry (Class 57)
Lesson Title
Using Congruent Triangles (3)
Overview
During the opener today students will continue to work on the CST practice. In addition, students will solve another construction puzzle involving circumscribing a triangle. The lesson for the day continues with either finishing our work with using congruent triangles to prove other facts or with our initial work with triangles which are the same shape, but not necessarily the same size-- similar triangles.
Textbook Sections
ยง4.6 (Txt. p.236) Isosceles, Equilateral, and Right 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.
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.
Turn-In (#56)
Txt. p. 55 #9-20
Handouts
CST Review
Assignment
Txt. p.258 #1-3, 7-9, 13-15, 22, 23, 37, 38
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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