1. Butterflies, Pinwheels and Wallpaper 4.2 & 4.3
Similarity Check
Butterflies, Pinwheels and Wallpaper 4.2 & 4.3

2. Learning Goal 1 (8.G.A.3 & 4):
The student will understand and use informal arguments to prove congruency and similarity using physical models, transparencies or geometry software. 4 3 2 1
In addition to level 3.0 and above and beyond what was taught in class, I may:
Make connection with real-world situations
Make connection with other concepts in math
Make connection with other content areas.
I understand and use informal arguments to prove congruency and similarity using physical models, transparencies or geometry software.
informally prove similarity of triangles
Use scale factors to create and analyze dilations.
I understand congruency and similarity using physical models, transparencies or geometry software.
construct triangles
Calculate dilations with scale factors.
With help from the
teacher, I have
partial success
with the unit content.
Even with help, I have no success with the unit content.

3. What strategies could you use to check the similarity of two figures?
How could measurements help you?
How could scale factors help you?
How could a sequence of transformations help you?
What strategies could you use to check the similarity of two figures?

4. Are the two figures similar?
9 cm
Measure parts of both figures.
How do we use these numbers to determine if the figures are similar?
Find the scale factor.
8 ÷ 24 = 1/3
3 ÷ 9 = 1/3
Since the scale factor is the same for both sets of sides, the figures are similar.
24 cm
3 cm
8 cm

5. What sequence of transformations changed the red figure into the brown figure?
9 cm
It could have been a 90˚ clockwise rotation followed by a dilation with a scale factor of 1/3.
Is it possible that it could have been a dilation with a scale factor of 1/3 then a 90˚ clockwise rotation?
24 cm
3 cm
8 cm

6. Labsheet 4.2