Calculating the angle between two 3d Vector's?

I calculated the angle between two normalized vectors, but the atan2d(cross,dot) gives me 3 values, wich when added result in the angle itself, is this normal?, Why does it give me three values? what does every value represent? I am using it to calculate joint angles with kinect, but my teachers asked me what were those three values and I honestly don't know, can you help me?