Answer:
22.9 yards
Explanation:
Since b² = a² - c² where a = vertex of major axis, 2a = 50 yards the length of the major axis. So , a = 50/2 = 25 yards. c = focus of chamber = 10 yards from center and b = vertex of minor axis.
So, b = ±√(a² - c²)
= ±√(25² - 10²)
= ±√(625 - 100)
= ±√525
= ±22.91 yards
≅ ± 22.9 yards
Since b = length of minor axis from center of chamber = 22.91 yards. So, he should build the whisper chamber 22.9 yards out from the center of the chamber.