(a)
Identify the percent of change as an increase or decrease. 2 dogs to 4 dogs

this is a percent of change increase.

Step-by-step explanation:

you want to use the formula,

new value - original value

        original value               * 100

now that we wrote the formula down, you substitute the numbers in. 2 is the original value and 4 is the new value.

4 - 2

  2   * 100

2

_

2 * 100

now that we find the amount of change, we could do this in two ways. divide the fraction first then multiply that by 100 OR multiply the numerator by 100 first then divide that by the denominator.

first way :

2

_

2  * 100

1 * 100 = 100% increase

second way :

2

_

2  * 100

200

___

 2  = 100% increase

3

step-by-step explanation:

divide 13.5 by 9 to get the scale factor. it equals 1.5

2 * 1.5 = 3