For a better understanding of the explanation provided here please go through the diagram in the attachment given below.
As we can see from the diagram of the congruent triangles ABC and FGH, the vertices A,B,C of [tex] \Delta ABC [/tex] correspond to the vertices F,G,H of [tex] \Delta FGH [/tex], so the corresponding sides must correspond too. Thus, AB corresponds to FG, BC corresponds to GH and CA corresponds to GF.
Now, we know that BC=10.4. Therefore, it's corresponding side GH must be 10.4 too because they are corresponding sides of a congruent triangle.
Thus, GH=10.4 is the correct answer.
