Impact angle help needed.

I am new to the forum, and it has been many years since I have had to deal with any problems like this one. My memory fails me on how to resolve this.

I am trying to determine the angle of impact of a projectile that has struck a vertical wall. The projectile was fired from an elevation, and I am trying to determine the angle.

The hole is oval in shape and it 8mm high by 4mm wide.

Sine (i) = minor/major

Sine (i) = 4/8

i = sin -1(4/8)

i = 30o

I believe I have this part correct, what I can not recall is the relation of this angle. Is this 30 degrees from the vertical plane, above the point of impact, or 30 degrees from below the point of impact?

Thanks for any help with this.

Mike