The waves from a radio station can reach a home receiver with two different paths. One is a straight-line path from the transmitter to the home, a distance of 31.0 km. The second path is with reflection from a storm cloud. Suppose that this reflection takes place at a point midway among receiver and transmitter. If the wavelength broadcast with the radio station is425 m, find the minimum height of the storm cloud that will produce destructive interference among the direct and reflected beams. (Suppose no phase changes on reflection.)