Friday, January 30, 2009
Geometry (Class 46)
Lesson Title
Proving Triangles Congruent (2)
Overview
During the opener for today’s class students have the opportunity to analyze, and make corrections to, two “student” proofs from the first semester final. The lesson for the day focuses on proving triangles congruent by identifying angle and side combinations that force congruence: SSS, SAS, ASA
Textbook Sections
§4.3 (Txt. p.212) Proving Triangles Congruent
Vocabulary
construction
straight edge
arc
radius
center
diameter
adjacent
opposite
included
non-included
Key Attitudes
Math is about being convinced a statement is always true.
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!
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 construct a triangle given given two sides and a non-included angle (SSA).
I can construct parallel lines.
I can construct the midpoint of a segment.
I can construct a triangle given the lengths of its three sides (SSS).
I can construct a triangle given its three angles (AAA).
I can construct a triangle given two adjacent sides and an included angle (SAS).
I can construct a triangle given two angles and the included side (ASA)
I can construct a triangle given two angles and the non-included side (AAS).
I can construct parallel lines.
I can construct the midpoint of a segment.
I can construct a triangle given the lengths of its three sides (SSS).
I can construct a triangle given its three angles (AAA).
I can construct a triangle given two adjacent sides and an included angle (SAS).
I can construct a triangle given two angles and the included side (ASA)
I can construct a triangle given two angles and the non-included side (AAS).
Turn-In (#45)
Txt. p.298 #6-20
Handouts
Chapter 4- Lesson 3: Proving Triangles Congruent
Assignment
Final Exam Free Response Corrections
Txt. p.298 #21-25, 42-46
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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