OG p. 260 ; pr / exercise 9

[irs031]

In the figure below AB=BC=CD. If the area of CDE is 42, what is the area of triangle ADG?

The provided answer is 378, however there is no explanation. It is clear that the problem has something to do with similar triangles and ratios, however I drew blank on this one? I can't find a clear relationship that would lead me to the correct answer. We don't know any sides of any of the triangles, only that the area of CDE is 42, that means the product of the two legs is 84. The hypotenuse of the largest triangle AGD is 3x the hypotenuse of the smallest triangle CDE. Again, this leads nowhere?
Thanks in advance for your help.

[tommywallach]

This question was answered previously, over here:

https://www.manhattanprep.com/gre/forum ... t9450.html

-t