Answer:
The scale factor used was 2
Explanation:
see the attached figure with letters to better understand the problem
we know that
A dilation is a non-rigid transformation that produce similar figures
If two figures are similar then the ratio of its corresponding sides is proportional and this ratio is called the scale factor
In this problem the dilation going from the grey triangle to the yellow triangle is an enlargement and its equal to the quotient length side AC by length side DE (corresponding sides)
we have
--->absolute value of the difference of the x-coordinates
--->absolute value of the difference of the x-coordinates
![(AC)/(DE)=(12)/(6)=2](https://img.qammunity.org/2021/formulas/mathematics/high-school/g85k2guakyut7g85g1tqv6oqumzh0b8pws.png)
therefore
The scale factor used was 2