Question

ABC is a dilation image of DEF. What is the scale factor?

Answer 1

The complete question in the attached figure

we know that
length side AB=8 units
length side DE=4 units


[ABC]=[DEF]*[scale factor]
then
[scale factor ]=[ABC]/[DEF]---------> 8/4--------> 2

the answer is
the scale factor for a dilation image of DEF to obtain ABC is 2