plane equation

hi
im trying to compare 2 planes in script. planes which i need to compare are from mesh. i choose triangles points that represents one plane and i need to find out if there is another tree points which lays in this plane. i can find two planes which are parallel (they have same normal vector), but i need to find exact same plane. is there any function on it in unity, or can you guys tell me some advice?

Easy

if (normals are parallel)
if (Vector3.Dot(pointInPlane - pointInOtherPlane, normal) == 0f)
Debug.Log("It is the same plane");

You are welcome.