The corresponding sides of `deltaabc` and `deltadef` have equal lengths. the area of `deltaabc` is 4 square units, and the longest side of `deltadef` is 5 units long. what is the area of `deltadef`?

Since for the two triangles, the three pairs of corresponding sides are congruent, then the triangles are congruent and their areas are equal.

area = 4 square units

where's the diagrams?

goog may have it for you