A stereo system is being installed in a room with a rectangular floor measuring

18

feet by

9

feet and

a

7

-foot

ceiling. The stereo amplifier is on the floor in one corner of the room. A speaker is at the ceiling in the opposite corner of the room. You must run a wire from the amplifier to the speaker, and the wire must run along the floor or walls (not through the air). What is the shortest length of wire you can use for the connection? (Hint: Turn the problem into an equivalent simpler problem by imagining cutting the room along its vertical corners and unfolding it so that it is flat. You will be able to apply the Pythagorean theorem.)

The shortest length of wire that can be used is

nothing

ft.