To indicate that the triangles in each pair are congruent, you can write the following statement: "Triangle ABC is congruent to triangle AFG."
This statement means that triangle ABC and triangle AFG have the same size and shape.
Another way to write the statement is:
"Triangle ACB is congruent to triangle AGF."
Both statements mean that the corresponding sides and angles of the triangles are equal, and therefore, the triangles are congruent.
In general, when indicating congruence between two triangles, you need to list the corresponding vertices in the same order. In this case, we have triangle ABC and triangle AFG, so we can say that triangle ABC is congruent to triangle AFG.