Determining Altitude

        / | \
       /  |  \
     /    O   \
    /   .   .  \
  /x .        .z\
 /. w         y .\
Two observers, A & B, are a distance D apart on flat ground and are both looking at the same object C above them (just for the sake of argument, let's say it's the point of maximum height of a water rocket.) With the angles they measure, they want to determine the height of C above the ground.

Assume that point O on the ground is directly below C (AOC and BOC are right angles).
Angles w (OAB) and y (OBA) are measured in the horizontal plane.
Angles x (OAC) and z (OBC) are measured vertically.

Find OC in terms of D and the necessary angles (I don't think all of the angles will be needed.)

Follow-Up: Many people have quickly found that the two lower angles (w,y) and one upper angle (x,z) can be used to find OC. Can OC be found with just one of (w,y) and both of (x,z)?

Source: Original (personal necessity...) A good starting place for water rocketry is:

Mail to Ken