A whispering chamber is an elliptically arched chamber. A unique feature of a whispering chamber is that when a person standing at one focus of the ellipse whispers, he can be heard by a person standing at the other focus, regardless of the dimensions of the ellipse from which the dome is built.
Suppose that the dimensions of the ellipse used to create a whispering dome is 180 feet by 420 feet. Angela stands at one focus, and Zach stands at the other focus.
How far apart are Angela and Zach?