We want to name the segment in △ DEF that is congruent to AC. Let's carefully consider observe the diagram. We can see that there are markings on all sides of the triangles. These markings show the congruent corresponding sides of both triangles. AC is the side with three markings. The segment in △ DEF that is congruent to this must also have three markings.
With this information, we can confirm that the segment in △ DEF that is congruent to AC is DF.
Extra
Remaining Corresponding Parts
Let's identify the remaining corresponding parts of the triangles. Remember that the sides with the same number of markings are congruent, so the congruent sides are as follows.
Congruent Sides
AC≅DF
AB≅DE
BC≅EF
When identifying the congruent angles, note that the angles with the same number of markings are congruent. We will also list them.
Congruent Angles
∠ACB≅∠DFE
∠CAB≅∠FDE
∠ABC≅∠DEF
