1. Scale Factor and Dilation
Part 2

2. Draw a rectangle on your graph paper with dimensions of 6cm by 4cm
Draw another rectangle on your graph paper where the above dimensions have been multiplied by a scale factor of 2
8cm
12cm
Length
width
perimeter
area
6cm
4cm
20cm
24cm²
12cm
8cm
40cm
96cm²

3. Draw a rectangle on your graph paper with dimensions of 6cm by 4cm
Draw another rectangle on your graph paper where the above dimensions have been multiplied by a scale factor of 3
12cm
18cm
Length
width
perimeter
area
6cm
4cm
20cm
24cm²
18cm
12cm
60cm
216cm²

4. The rectangle below will be dilated by a scale factor of 3
The rectangle below will be dilated by a scale factor of 3. What is the new rectangle’s area and perimeter? 2m
6 m
10m
30m
P =
P =
P = 24 m
P = 72 m
A = 2 • 10
A = 6 • 30
A = 20 m²
A = 180 m²

5. Sooo….. What really happened??
Old perimeter
Scale factor 3
New perimeter
P = 24 m
P = 72 m
24 • 3 = 72
Multiply the old perimeter by the scale factor to get the new perimeter
Old area
Scale factor 3
New area
A = 20 m²
A = 180 m²
20 • 3 ≠ 180
20 • 9 = 180
20 • 3² = 180
Multiply the old area by the scale factor squared to get the new area

6. Which statement best describes the change in the perimeter of a rectangle if all of its side lengths are multiplied by 4?
A The new perimeter will be 12 times as large as the perimeter of the original rectangle
B The new perimeter will be 16 times as large as the perimeter of the original rectangle
C The new perimeter will be 4 times as large as the perimeter of the original rectangle
D The new perimeter will be 8 times as large as the perimeter of the original rectangle

7. Which statement best describes the change in the area of a rectangle if all of its side lengths are multiplied by 4?
A The new area will be 12 times as large as the area of the original rectangle
B The new area will be 16 times as large as the area of the original rectangle
C The new area will be 4 times as large as the area of the original rectangle
D The new area will be 8 times as large as the area of the original rectangle

8. Answer bank for CBA review # 2
3.02 9 11 12 18 20 60 68
112.35
113.04
310
400
1536

9. The rectangle below will be dilated by a scale factor of 3
The rectangle below will be dilated by a scale factor of 3. What is the new rectangle’s area and perimeter?
P =
P =
P =
P =
A =
A =
A =
A =

10. Sooo….. What really happened??
Old perimeter
Scale factor 3
New perimeter
P =
P =
Multiply the _____________ by the scale factor to get the new perimeter
Old area
Scale factor 3
New area
A =
A =
20 •
20 •
20 •
Multiply the _________by the scale factor _______ to get the new area

11. Which statement best describes the change in the perimeter of a rectangle if all of its side lengths are multiplied by 4?
The new perimeter will be 12 times as large as the perimeter of the original rectangle
The new perimeter will be 16 times as large as the perimeter of the original rectangle
The new perimeter will be 4 times as large as the perimeter of the original rectangle
The new perimeter will be 8 times as large as the perimeter of the original rectangle

12. Which statement best describes the change in the area of a rectangle if all of its side lengths are multiplied by 4?
The new area will be 12 times as large as the area of the original rectangle
The new area will be 16 times as large as the area of the original rectangle
The new area will be 4 times as large as the area of the original rectangle
The new area will be 8 times as large as the area of the original rectangle