we know that
1) scale factor is equal to
2) The ratio of the perimeters of the triangles is equal to the ratio of the measures of the sides
3) the longest side of ∆ABC=[scale factor]*the longest side of ∆DEF
the longest side of ∆ABC=
the longest side of ∆ABC= units
the answer part a) is
the longest side of ∆ABC is units
Part b)
The ratio of the area of ∆ABC to the area of ∆DEF is equal to the scale factor squared
so
therefore
the answer part b) is
The ratio of the area of ∆ABC to the area of ∆DEF is