1. The problem is about understanding if the equality $AD = BA$ is the same as $BA = AD$ in the context of triangle congruency. 2. In mathematics, equality is symmetric, meaning if $AD = BA$, then it is also true that $BA = AD$. 3. This means writing $BA = AD$ instead of $AD = BA$ is correct and does not change the meaning. 4. So, both expressions represent the same equality and are valid in proving congruency of triangles or any other mathematical context. Final answer: Yes, writing $BA = AD$ is correct and equivalent to $AD = BA$.