In $\triangle A B C$ and $\triangle D E F$ we have $\frac{A B}{D F}=\frac{B C}{D E}=\frac{A C}{E F}$, then which of the following is true?

$\triangle B C A \sim \triangle D E F$

Now, we have,

\(\frac{AB}{DF}\) = \(\frac{BC}{DE}\) = \(\frac{AC}{EF}\)

= \(\frac{BC}{DE}\) = \(\frac{CA}{EF}\) = \(\frac{BA}{DF}\)

So, side BC is corresponding to DE, CA is corresponding to EF and BA is corresponding to DF.

Therefore, \(\Delta \)BCA is similar to \(\Delta \)DEF.