Answer:
SImilar triangles are: ABC, DBG, DEF, and BEH.
Explanation:
There are clealy four well defined triangles in the image:
ABC, DBG, DEF, and BEH.
Given the parallelism of the mentioned lines, one can conclude that when those lines parallel to different sides of the triangle ABC for example (to sides AC and CB), intersect, they will also intersect giving similar angles . That is: angle ACB must equal angle DGB, angle DFE, and angle BHE. Apart from that, the angles around the bases of all four triangles must be equal since they come from parallel lines. That is:
(1) angles BAC, BDG, BDF, and EBH must be equal to each other, and
2) angles ABC, DBG, DEF, and BEH must be equal to each other.
Therefore we have four triangles with congruent angles, which make them similar triangles.