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 Figures4. Tonight’s Assignment– Follow up 3.1

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.

3.1 Identifying Similar Figures

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.

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.

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?

Warm-up Tuesday

1. Choose the pair of similar figures.

a) Z and Yb) V and Tc) X and Yd) Y and W

2. Find another pair of similar figures. Explain your reasoning.

Quarter 2: Week 5

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.

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?

Warm-up: Wednesday

• Are the following rectangles similar1. 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.

Quarter 2: Week 4

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-tiles4. Tonight’s assignment– Workbook p. 181

3.2 Building

with Rep-tiles

• 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?

• 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 rep-tile and the second is not. Look at the shapes carefully, and tell me what you think a rep-tile is.

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?

REP - TILES

Not rep-tiles

Copy table in your journal….Shape Sketch a larger

shapeNumber of

rep-tiles usedScale factor

from small to large

Scale factor from large to

small

4 22

1

Warm-up Thursday

• Find the missing values.1. x = ?

2. a= ?

Quarter 2: Week 5

3 28

x

a

6

42 42

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 3.24. Discuss follow up 3.25. Turn in Weekly Assignment Sheet