A person in a whispering gallery standing at one focus of the ellipse can whisper and be
Chapter 8, Problem 67(choose chapter or problem)
A person in a whispering gallery standing at one focus of the ellipse can whisper and be heard by a person standing at the other focus because all the sound waves that reach the ceiling are reflected to the other person. If a whispering gallery has a length of 120 feet, and the foci are located 30 feet from the center, find the height of the ceiling at the center.
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