1. Bell work Find the perimeter and area of the two figures below.3 4
Perimeter = 10
Area = 4
Perimeter = 12
Area = 9 1 3
Open your books to Stretching & Shrinking, Page 38
Have a piece of paper and pencil ready for notes.

2. Section 3.1 similar figures

3. Similar Polygons

4. Similar Polygons

5. Similar Polygons

6. Similar Polygons

7. Similar Polygons IMPORTANT VOCABULARY
Rep-tile – A figure you can use to make a larger, similar version of the original.

8. Unit 3.1 Rep-tile Quadrilaterals
In the pencil box on your desk you will find plastic bags with the following shapes.
A non-square rectangle
A non-rectangular parallelogram
A trapezoid
Each team member will need four of each shape.

9. Are They Rep-tiles? All three shapes are rep-tiles.
A. Which of these shapes can fit together to make a larger shape that is similar to the original?
Make a sketch to show how the copies fit together.
All three shapes are rep-tiles.

10. Use Your Sketches from Question A
1. What is the scale factor from the original figure to the larger figure?
2. How does the perimeter of the new figure compare to the original?
The scale factor is 2. The lengths of the new shape are two times as long as the original.
The perimeter doubles because each side is twice as long as the original.
The perimeter goes up by the scale factor.

11. Use Your Sketches from Question A
1. How does the area of the new figure compare to the original?
The area is four times as large.
Four of the original shape can fit in the new figure.
The area goes up by the scale factor squared.

12. Work as a Team Scale Factor: 3 Scale Factor: 4 Sides: 3x longer
Sides: 4x bigger
Perimeter: 3x bigger
Perimeter: 4x bigger
Area: 9x bigger
Area: 16x bigger

13. ACE Questions, Page 50, #22
Supplementary Angles – Two angles that form a straight line. The sum of the angles is 180 degrees.

14. ACE Questions, Page 50, #22 Which angles above are supplementary?
a and b a and c b and 120
d and e d and g e and f

15. ACE Questions, Page 50, #22
What are the measures of the missing angles?
a = 120 d = 120 g = 60
b = 60 e = 60
c = 60 f = 120

16. ACE Questions, Page 50, #24 50 degrees
Find the measure of angle R. Explain how you can find the measure of angle C.

17. ACE Questions, Page 50, #24 Angle R = 50 degrees Angle Q = 40 degrees
Find the measure of angle R and Q.
Angle R = 50 degrees 50
Angle Q = 40 degrees 40

18. EXIT SLIP
Answer the following in complete thought sentences.
What happens to the side lengths, perimeter and area of shape that is enlarged by a scale factor of 2?
Use at least two complete sentences.