The waves from a radio station can reach a home receiver by two paths. One is a straight-line path from transmitter to home, a distance of 22.0 km. The second path is by reflection from the ionosphere (a layer of ionized air molecules high in the atmosphere). Assume that this reflection takes place at a point midway between receiver and transmitter and that the wavelength broadcast by the radio station is 355 m. Find the minimum height of the ionospheric layer that produces destructive interference between the direct and reflected beams.