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1. Lesson 35
Obj: Students will recognize similar and congruent polygons.

2. Vocabulary
• Similar – same shape, different size
• Congruent – same shape, same size
• Corresponding Angles – angles that match up
• Corresponding Sides – sides that match up
• Similar Polygons – corresponding angles and proportional sides
• Congruent Polygons – corresponding angles and sides

3. Which two quadrilaterals are similar?
A B C D
12 8 4 12
8 6 6 13

4. Side-Side-Side- Triangle Similarity
If two triangles have proportional corresponding side lengths, then the triangles are similar.
A D
4 6
8 12
F E
8
B 16 C

5. Angle-Angle-Angle Similarity
If the angles of one triangle are congruent to the angles of another triangle, then the triangles
are similar and their corresponding side lengths are proportional.
U Y
R

6. Find the missing side
J
15 5
X
3
4
12

7. Solve
• If 1 inch on the drawing represents 4 feet, then what is the scale factor from
the drawing to the actual building?
• What is the length and width of a room that is 5in by 4in on the drawing?

8. Use these triangles to solve the following questions
P
A Z J
B C R Q X Y K L
 Which triangle is congruent to ⊿퐴퐵퐶?
 Which triangle is similar but not congruent to ⊿푋푌푍?
 Which triangle is not similar to ⊿푃푄푅?
 Which angle in ⊿푍푌푋corresponds to ∠퐴 in ⊿퐴퐵퐶?
 Which side of ⊿푃푅푄 corresponds to side XY in ⊿푍푌푋?