Answer: The scale factor of dilation is 2:1
Explanation: You can see that the sides of the blue triangle are of lenght 4 and 3, and for the red triangle, the lenghts are 8 and 6 (so the lenghts are doubled)
Here we can see that the dilation has a factor of dilation = 2 (meaning that the red triangle sides have two times the lenghts of the blue triangle sides). The factor can be written as 2:1