Each side of a triangle ABC has been extended by its size, giving rise to a new triangle. What is the ratio of the areas of these triangles?

Question

In a triangle ABC each side has been extended by it's length, we mark the edges of the segments D,E,F and draw the triangle DEF. Image What is the ratio of the areas between the two triangles. Edit: I try to draw it on geogebra and found out it's 1:7 but I have no idea how to prove it.