If triangle ABC is congruent to triangle XYZ, then which of the following is congruent to CA?
AB, XY, YZ, ZX

Solution:

If triangle ABC is congruent to triangle XYZ,

The congruence is denoted as ABC ≅XYZ

From which we know that 

∠A ≅ ∠X

∠B ≅ ∠Y

∠C ≅ ∠Z

and

AB ≅ XY

BC ≅ YZ

AC ≅ XZ

From this we get that ZX is congruent to CA.

Therefore, ZX is congruent to CA.

If triangle ABC is congruent to triangle XYZ, then which of the following is congruent to CA?

Summary:

If triangle ABC is congruent to triangle XYZ, ZX is congruent to CA.