Make sure you have the triangles' corresponding parts aligned in order to see how the scale factor is applied.
segment AB corresponds to segment DE: 6:48 =>reduces to 1:8
segment BC corresponds to segment EF: 6:48 => 1:8
segment CA corresponds to segment FD: 4:32=> 1:8
Since you are looking for the scale factor of ABC to DEF the answer is 8 because DEF is 8 times larger than ABC.
what is the sacle factore?