Answer:
To prove that triangle ABF is congruent to triangle EDG, we need to show that the three sides of triangle ABF are congruent to the corresponding three sides of triangle EDG.
Since we are given that BC is congruent to DC, AB is congruent to ED, and AG is congruent to EF, we can conclude that the three sides of triangle ABF are congruent to the corresponding three sides of triangle EDG. Therefore, triangle ABF is congruent to triangle EDG.