Dilations
There are two types of dilation:
Enlargement: produces a larger image.
Reduction: produces a smaller image.
In this case, the blue figure is larger than the red one, then this is an enlargement.
Scale factor
In order to find the scale factor we just have to find the number that multiplies each side. We find it by dividing the measure of one side of the red figure by the measure of the corresponding side of the blue figure.
We are going to select the sides
AB and A'B'.
We can observe that
A'B' = 6
AB =3
Then
scale factor = 6 ÷ 3 = 2
It does not matter which couple of corresponding sides we select. The division should result in the same number.
Then, our scale factor is 2 (the blue figure is two times the red figure)