1. Effect of Change
The effects on perimeter, area, and volume when dimensions are changed proportionally.

2. Perimeter of a rectangle
How would the perimeter change if the dimensions of the rectangle are doubled?
14 ft.
8 ft.
7 ft.
4 ft.

3. Formula P = 2 • l + 2 • w How do the perimeters change?
7 by 4
Formula P = 2 • l + 2 • w
Original Problem
P = 2(7) + 2(4)
P =
P = 22
Proportional Change
P = 2(7 doubled) + 2(4 doubled)
P = 2(14) + 2(8)
P =
P = 44
How do the perimeters change?
Divide the new perimeter by the original perimeter. When the dimensions doubled, the perimeter doubled

4. Solve the same problem using the effect of change formula
How would the perimeter change if the dimensions of the rectangle are doubled?
(dimension change) PAV#
7 ft.
(2) = 2
4 ft.
The new perimeter will be double the original perimeter

5. Area of a rectangle
How would the area change if the dimensions of the rectangle are doubled?
14 ft.
8 ft.
7 ft.
4 ft.

6. Formula A = l • w How do the areas change? Original Problem A = 7(4)
7 by 4
Formula A = l • w
Original Problem
A = 7(4)
A = 28
Proportional Change
A = (7 doubled)(4 doubled)
A = (7 • 2)(4 • 2)
A = (14)(8)
A = 112
How do the areas change?
Divide the new area by the original area. When the dimensions doubled the area increased by 4 times the original size

7. Solve the same problem using the effect of change formula
How would the area change if the dimensions of the rectangle are doubled?
(dimension change) PAV#
7 ft.
(2) 2 = 4
4 ft.
The new area will be 4 times the original area

8. Volume of a rectangular prism
How would the volume change if the dimensions are quadrupled?
3 ft.
2 ft.
4 ft.

9. Formula V = l • w • h How do the volumes change? Original Problem
4 by 2 by 3
Formula V = l • w • h
Original Problem
V = 4(2)(3)
V = 24
Proportional Change
V = (4 • 4)(2 • 4)(3 • 4)
V = (16)(8) (12)
V = 1536
How do the volumes change?
Divide the new volume by the original volume.
When the dimensions quadrupled, the volume increased by 64 times the size of the original

10. Solve the same problem using the effect of change formula
How would the volume change if the dimensions of the shape are quadrupled?
(scale factor) PAV
3 ft.
(4) 3 = 64
2 ft.
The new volume will be 64 times the original volume
4 ft.

11. What to do if NO dimensions are given
Do the math...pick “baby numbers” to compute if no numbers are given. Apply scale factor change. Divide.
Use the Effect of change
formula (scale factor) PAV#

12. Perimeter of a rectangle
How would the area change if the dimensions of the rectangle are 5 times the original size?

13. Geometry formula method
How would the area change if the dimensions of the rectangle are 5 times the original size?
Pick “baby numbers” 3
A = 150 10 2
A = 6
25 times bigger 15

14. Effect of Change Formula
How would the area change if the dimensions of the rectangle are 5 times the original size?
(scale factor) PAV#
(5) 2 = 25 times bigger

15. Volume of a rectangular prism
What would the new perimeter be if the dimensions are quadrupled?
4 ft.
3 ft.

16. Volume of a rectangular prism
What would the new area be if the dimensions are tripled?
4 ft.
6 ft.

17. Volume of a rectangular prism
What would the new volume be if the dimensions are doubled?
4 ft.
3 ft.
6 ft.