The error in finding the scale factor is not differentiating the length of the bigger and smaller triangle.
The scale factor of the dilation is 3
What is the error in finding the scale factor of the dilation?
A scale factor is the ratio between the scale of a given original object and a new object.
The total length = 12
The length of the smaller triangle = 3
The length of the larger triangle = The total length - The length of the smaller triangle
= 12 - 3
= 9
Hence,
Scale factor = Bigger triangle : Smaller triangle
= 9 : 3
= 9/3
= 3