Chapter 4 - Congruent Triangles - 4-7 Congruence in Overlapping Triangles - Practice and Problem-Solving Exercises - Page 271: 29

$\triangle$DEF is congruent to $\triangle$GFE by SAS (Side-Angle-Side).

Each triangle contains a pair of congruent sides, which are marked by dashes, and a congruent angle (also marked). The sides on each triangle forms the angle, so the triangles are congruent by SAS (which stands for Side-(Included)Angle-Side) theorem.