Hey Korman, there are right angles between the planes containing x and y and the planes containing x and E. But x does not equal 2*18.4. that seems intuitive, and is what I first thought as well, but the model I made shows how the projection of the two equal angles 'a' onto a second plane creates two new angles.. if that makes sense.

I may need to go back to the old text books, seems like this should be easily solvable with the right technique.