An aircraft (at Z) is spotted by two observers (at X and Y) who are L = 1050 feet apart. As the airplane passes over the line joining them, each observer takes a sighting of the angle of elevation to the plane, as indicated in the figure. If A = 45°, and B = 20°, how high is the airplane?
The elevation of the plane is approximately $\boxed{}$ feet.
(Round the final answer to two decimal places as needed. Round all intermediate values to four decimal places as needed.)