The angle from the Spotlight
is 75º, the angle of the elevation of the spotlight is 45º, so the 3rd angle is
60º(180-75-45 =60).
Use the law of sines to find the distance "s" from the observer to
the cloud:
515/sin(60) = s/sin(75)
s = 515*sin(75)/sin(60)
s = 574.41 meters
Then, the height is s*sin(45)
s = 406.17 meters