56. The transmitter site of radio station WGGW and the transmitter site of another radio station, WGWB, are on the same highway 100 miles apart. The radio signal from the transmitter site of WGWB can be received
only within a radius of 60 miles in all directions from
the WGWB transmitter site. For how many miles along
the highway can the radio signals of both stations be received?
(Note: Assume the highway is straight.)