1. Welcome to Pre-Algebra
Monday: Quarter 2….Week 5
1. Please write your homework down in your
agenda book for the week.
2. Return and go over Quiz on Investigation 1
and 2
3. 3.1 Indentify Similar Figures
4. Tonight’s Assignment
– Follow up 3.1

2. Investigation 3:
Patterns of Similar
Figures
In the last investigation, you
met the Wump family. You
found that Mug, Bug, and Zug
are similar- they have exactly
the same shape. You also
discovered that, to make a
figure that is similar to a given
figure, you keep the same
angles and multiply each length
of the original figure by the
same number. For example, to
go from Mug to Zug, you use
the same angles and multiply
each length by 2. To make a
smaller member of the Wump
family, you could shrink Mug by
keeping the same angles and
multiplying each length by a
number less than 1, such as 0.5.

3. How good are you at spotting changes in a
figure’s shape? Can you look at two figures
and decide whether they are similar? In the
last investigation, you learned some
mathematical ideas about what makes figures
similar. Here, you will use your visual
perception to predict which figures might be
similar, and then use mathematics to check
your predictions.

4. Problem 3.1
• Examine the four sets of
polygons on Labsheet
3.1. Two shapes in each
set are similar, and the
other is an imposter.
• In each set, which
polygons are similar?
Explain your answers.
You may cut out the
polygons if it helps you
think about the question.

5. 3.1 Follow -up
1. For each pair of similar figures on Labsheet 3.1,
tell what number the side lengths of the small
figure must be multiplied by to get the side
lengths of the larger figure.(scale factor)
2. For each pair of similar figures on Labsheet 3.1,
tell what number the side lengths of the large
figure must be multiplied by to get the side
lengths of the small figure. (scale factor)
3. How are the scale factors in parts 1 and 2
related?

6. Quarter 2: Week 5
Warm-up Tuesday
1. Choose the pair of
similar figures.
a)
b)
c)
d)
Z and Y
V and T
X and Y
Y and W
2. Find another pair of
similar figures. Explain
your reasoning.

7. Welcome to Pre-Algebra
Tuesday
1. Please have your homework on your
desk and get started on your warm up.
2. Class discussion
– Follow up 3.1
3. Please work on your core workbook p.
177 – 179. What you do not finish is
homework.

8. 3.1 Follow -up
1. For each pair of similar figures on Labsheet
3.1, tell what number the side lengths of the
small figure must be multiplied by to get the
side lengths of the larger figure.(scale factor)
2. For each pair of similar figures on Labsheet
3.1, tell what number the side lengths of the
large figure must be multiplied by to get the
side lengths of the small figure. (scale factor)
3. How are the scale factors in parts 1 and 2
related?

9. Quarter 2: Week 4
Warm-up: Wednesday
• Are the following rectangles similar
1. A rectangle has a length of 10 and a width of
6. A larger rectangle has a length of 60 and a
width of 30.
2. A rectangle has a length of 7 and a width of
5. A larger rectangle has a length of 20 and a
width of 12.

10. Welcome to Pre-Algebra
Wednesday
1. Please have your homework on your desk
and get started on the warm up.
2. Please use a red pen to correct your
homework.
3. 3.2 Building with Rep-tiles
4. Tonight’s assignment
– Workbook p. 181

11. • A rep-tile is a shape whose
copies can be put together to
make a larger, similar shape.
The small triangle below is a
rep-tile. The two large
triangles are formed from
copies of this rep-tile. Can
you explain why each large
triangle is similar to the small
triangle?

12. • Today we will investigate several shapes to see
which of them are rep-tiles. I am going to
show you two shapes; the first shape is a reptile and the second is not. Look at the shapes
carefully, and tell me what you think a rep-tile
is.

13. Here are two more shapes. The
triangle is a rep-tile, but the hexagon is
not. Now what do you think a rep-tile
is?

14. Not rep-tiles
REP - TILES

15. Copy table in your journal….
Shape
Sketch a larger
shape
Number of
rep-tiles used
4
Scale factor
from small to
large
2
Scale factor
from large to
small
1
2

16. Quarter 2: Week 5
Warm-up Thursday
• Find the missing values.
1. x = ?
3
2
8
x
2. a= ?
4
2
2
a
6
4

17. Welcome to Pre-Algebra
Thursday
1. Please have your homework on your desk
and get started on your warm.
2. Please correct your homework with a red
pen
3. In groups complete follow up 3.2
4. Discuss follow up 3.2
5. Turn in Weekly Assignment Sheet