Answer:
The scale factor for the resultant rectangle is
units.
Step-by-step explanation:
Given two rectangles with sides 3 units and 7.5 units.
We have to find the scaling factors so that we can obtain bigger rectangle of 7.5 units from smaller rectangle of 3 units.
Scale factor is defined as the ratio of corresponding side of given figure to the corresponding side of resulting figure.
That is 
Here, 

Hence, the scale factor for the resultant rectangle is
units.
You can use the equation rise over Run you go up 4 and over 6 and you go down 2 and over 8 (im not sure if this helps)
Answer:
Step-by-step explanation:

Ratio of dog bark is 4:5
Multiply that by 20 each side
Ratio is now 80:100
So 80%
If they walk past 45 time you just have to multiply the ratio 4:5 by 9
36:45
So the dog would bark 36 times