Answer
△FGK and △KLF are congruent using Postulate 4-2 Side-Angle-Side (SAS) Postulate
Work Step by Step
Proof:
FG ≅ KL - given (Side)
FG ‖ KL - given
∠GFK ≅ ∠LKF - Alternate Interior Angles (Angle)
FK ≅ KF - Reflexive Property of Congruence (Side)
△FGK ≅ △KLF - Postulate 4-2 Side-Angle-Side (SAS) Postulate