I can't find the right answer for this question. Two planes have left the L. airport.

I can't find the right answer for this question.Two planes have left the L.A. airport. One plane is 70 miles west of the airport and has an altitude of 8 miles, while the other plane is 20 miles east of the airport and has an altitude of 2 miles. What is the distance between the planes? 4239 miles 4692 miles 3426 miles 6226 miles