como es lo correcto "la acta" o "el acta"?
"El acta", even though it is feminine, because the next word starts with a stressed "a". However, you have to write "El acta parlamentaria" and "La principal acta".
Caution: Lazarus´ explaination is absolutely correct, however this usage is for singular only. In plural, there is no conflict of an a and accented a next to one another so it is still las actas in plural.