Answer:
∠HDE
Explanation:
Vertical angles are congruent. When two lines cross, there are always two pairs of vertical angles formed. The vertical angles produced by lines GE and HF crossing at point D are ...
∠GDH and ∠EDF
∠FDG and ∠HDE . . . . . . the angle pair of interest
Angle HDE is congruent to angle FDG.