Friday, March 27, 2009
Geometry (Class 65)
Lesson Title
Similar Triangles (7)
Overview
The opener for the day focuses on simplifying and unsimplifying square roots. Students also apply these skills to right triangles via the Pythagorean Theorem. The lesson for the day focuses on proving triangles similar using SAS. During the last part of the class students will be taking Test 11 which focuses on proving triangles similar, using similar triangles, perfect square trinomials.
Textbook Sections
§8.5 (Txt. p.488) Proving Triangles are Similar
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 recognize a perfect square trinomial.
I can factor a perfect square trinomial by inspection quickly.
I can solve a perfect square trinomial equation by factoring.
I can simplify square roots.
I can match angles and sides of similar triangles.
I can write similarity statements for two similar triangles.
I can write a proportionality statement for two similar triangles.
I can translate between similarity statements and proportionality statements as related to similar triangles.
I can determine which of the triangle similarity postulates (SSS, AA, SAS) can be used to show that two triangles are similar
I can prove two triangles are similar by using SSS, AA, or SAS.
Turn-In (#64)
Txt. p.483 #39-45-47
Handouts
Proving Triangles Similar using SAS
Assignment
Txt. p.493 #6-14, 29
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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