1. 2-90. Decide if each pair of triangles below is similar
2-90.  Decide if each pair of triangles below is similar.  Use a flowchart to organize your facts & conclusion for each pair of ∆.
𝟖 𝟒 = 𝟗 𝟓 = 𝟏𝟒 𝟕 ?
𝟐 𝟏 ≠ 𝟗 𝟓 ≠ 𝟐 𝟏
No, they are not similar.
Proportion
Proportion
Reflexive Prop.
1&2 3
Warm Up 4

2. 2.3.2 Determining Similar Triangles
September 18, 2019
HW: 2-94 through 2-99

3. Objective
CO: SWBAT use the three triangle similarity conditions (AA ~, SAS ~, and SSS ~).
LO: SWBAT use flow charts to explain their reasoning as to why the triangles are similar.

4. Simultaneous Round Table
2-92.  Kamraan offers you a challenge.  Are the triangles similar?  How do you know? 1
Use a flowchart to organize your explanation.
Kamraan says, “These triangles aren’t just similar—they’re congruent!”  Is Kamraan correct?  What special value in your flowchart indicates that the triangles are congruent?
The ratio of the sides is one.
Write a conjecture (in “If…, then…” form) for your observation in part (b).  Then prove that it is true by justifying the conclusion using rigid transformations.
If the scale factor is one, then the triangles are congruent. (Use rotation)
Use an arrow diagram to express your conjecture from part (c).  Now that you have proved this conjecture, you may use this arrow diagram as a reason in proofs.
Scale factor = 1 → Congruent triangles 2 3
Proportion
Proportion
Flowchart:
Simultaneous Round Table
Questions:
Hot Potato 4

5. 2-93. Examine the triangles.
Are these triangles similar?  If so, make a flowchart justifying their similarity.
Charles has ΔCAT ~ ΔRUN as the conclusion of his flowchart.  Leesa has ΔNRU ~ ΔTCA as her conclusion.  Who is correct?  Why?
AreΔCAT and ΔRUN congruent? Explain how you know.
Determine all the missing side lengths and angle measures of ΔCAT and ΔRUN.
Optional
Proportion
Proportion