Wednesday, October 25, 2006
Geometry (Class 20)
Overview
§4.4 (p.220) Proving Triangles Congruent using ASA and AAS.
We continue our work proving triangles congruent. We add two new congruence postulates to the one we have already developed. If time permits we also examine why SSA is not a congruence postulate.
Key Ideas
To prove triangles congruent you need three pieces of information.
When writing proofs for congruent triangles, first decide which congruence postulate you are going to use, then work your proof to establish congruence of each pair of angles or sides.
It is helpful to identify where in the proof you have established each of the pieces by writing “S”, or “A”, to the left of the statement.
Vocabulary
non-included side
non-included angle
Assignment
Proofs for Practice #9
§4.4 (Txt. p.223) #8-10, 19, 20
§4.3 (Txt. p.216) #23, 24
Solving Systems of Equations Practice (Txt. p.796) #3, 9
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