So the ratio is at ¼ : 12, namely the drawing has ¼ inch to an actual 12 feet.
so, what would it be for an actual 15 feet on the drawing then?
The circumference is pi times the diameter of the circle. The radius is half of the diameter. In this case, the radius is then 36.
The sum of all the angle measures is 180 degrees, now lets set up some equations:

Thus x = 22
Hope that helps!
The answer is x=6, have a good day!