Because the shapes are similar find 1 side of the small shape and 1 side of the big shape that are in the same place/that are similar to each other.
The bottom part of both shapes have a number so let’s use those.
The numbers (in ratio form) are 8:24
The GCF (greatest common factor) that goes into both numbers is 8.
So divide each side by 8 (8 divided by 8 and 24 divided by 8)
Now you have 1:3. (Again, in ratio form)
This is your scale factor.
So in the top box put 1 and the bottom box put 3
SCALE FACTOR 1:3