Answer:
The area of the two-dimensional cross section is [tex]30\ ft^{2}[/tex]
Step-by-step explanation:
we know that
The two-dimensional cross section that is parallel to face ABC is a triangle congruent with the triangle ABC
Therefore
Calculate the area of triangle ABC
[tex]A=\frac{1}{2}(BC)(AB)[/tex]
we have that
Triangles ABC and DEF are congruent
so
[tex]BC=EF=12\ ft[/tex]
[tex]AB=5\ ft[/tex]
substitute
[tex]A=\frac{1}{2}(12)(5)=30\ ft^{2}[/tex]
