Question

How is triangle FGE similar to triangle CDE, find DE

Answer 1

They are similar because of the AAA similarity test

Since E is an opposite angle by the vertex then the angles are equal, and angle C and G are equal because they are alternate interior angles, similarly D and F are equal because they are alternate interior angles.

Then

(3x+2) /16 = (5x+1)/10

solving the equation x=0.08

and DE would be 1.4