#Python 2, 100 bytes
The question currently has incorrect examples (see my comments), so I went with the inequality that includes a
and b
, rather than the example which leaves out those solutions.
from math import*
x,a,b=input()
while a<=b:
if round(sin(pi*a/180),5)==x:print a
a=round(a+.001,3)
Try it online