Chapter 4 - Congruent Triangles - 4-3 Triangle Congruence by ASA and AAS - Practice and Problem-Solving Exercises - Page 238: 9

$\triangle{ACB}$ and $\triangle{EFD}$

In order to prove congruence using ASA, it is necessary that the side marked as congruent is between the two angles marked as congruent. However, we see that for triangle GHI, there is only one angle that is marked as congruent. Because of this, it is impossible to establish congruence using ASA.