A = (13.0492, 30.9498, 9.01115),

B = (21.1958196, 12.05024361, 13.187175),

C = (1.97687, 4.68868, 17.3632),

D = (-6.169749596, 23.58823639, 13.187175),

O = (7.513035, 17.81924, 13.187175)
At the moment I'm having trouble finding the 4 points A', B', C' and D' where the cube's corners intersect the ground. Another two properties I need to find are the area that this A'B'C'D' plane on the ground encloses and also what volume of the cube is above or below the ground. I'm so sorry to be bothering you but any advice at all in approaching this would be of huge benefit to me.