Answer:
60 feet from the center.
Step-by-step explanation:
As this it was designed as whispering gallery, and we know the whole length of the hall, and the highness of the ceiling we can use the following expression:
c² = a² - b² (1)
Where:
c: Length from center to foci.
a: length of half the hall.
b: length of the ceiling.
Replacing the given data into (1) we have:
c² = (130/2)² - (25)²
c = √65² - 500
c = √3600
Hope this helps
