Answer:
120
Step-by-step explanation:
If the dilation has a scale factor of 3, it means that each side of the polygon ABCD increased to 3 times the original length.
So, if the perimeter is the sum of the sides, we have:
[tex]P = AB + BC + CD + DA = 40[/tex]
[tex]P' = 3AB + 3BC + 3CD + 3DA[/tex]
[tex]P' = 3(AB + BC + CD + DA)[/tex]
[tex]P' = 3P = 120[/tex]
So the perimeter is also 3 times higher, with a length of 120.