An air traffic controller notices two signals from two planes on the radar monitor. One plane is at altitude 800 m and in a 19.2-km horizontal distance to the tower in a direction south of west. The second plane is at altitude 1100 m and its horizontal distance is 17.6 km and south of west. What is the distance between these planes?

An air traffic controller notices two signals from two planes on the radar monitor. One plane is at altitude 800 m and in a 19.2-km horizontal distance to the tower in a direction south of west. The second plane is at altitude 1100 m and its horizontal distance is 17.6 km and south of west. What is the distance between these planes?