An ellipsoid is a 3D shape whose cross sections are ellipses. A whispering gallery is a room with a half-ellipsoid ceiling. If one person whispers from one focus, another person can hear them clearly from the other focus. Suppose a whispering gallery has 5-foot walls. A cross section of the ceiling can be modeled by the ellipse shown below, centered at the origin with a horizontal major axis. If the room is 26 ft wide, and the whispering points are 10 ft apart, what is the maximum height of the ceiling? 10 26