Answer:
when same distance between the focus and Directrix
Explanation:
we know that when two parabola will be congruent if we find 2 point are at equal distance from focus point
so as if we align vertices and we get parallel and parabola open in same direction
and we know the parabola have same shape when focus and Directrix are aligned
so as that 2 parabola will congruent when they have the same distance between the focus and Directrix