The area of a triangle within a triangle
I've been confronted by what seems to be a very difficult geometry problem.
The questions asks how much smaller triangle DEF is from triangle ABC. Lines are constructed on each side at the 1/3 point (of the side) and go to a corresponding vertex. The lines essentially split each side of the triangle into 2 corresponding line segments, 1/3 and 2/3 the length of the entire side. The lines meet up to form the triangle DEF. ABC is not an equilateral triangle.
I attempted to use Heron's formula to find the area of ABC, but xyz for the sides didn't get me too far. I included an illustration of this problem in the attachment.
Thanks in advance for any help.