I guess you are talking about a triangle . The 3 angles add up to 180 degrees.
b + c = 180 - 25 = 155 degrees
When b > 51 degrees then
c <= 155 - 52
c <= 103 degrees
When b < 57
c >= 155 - 56
c >= 99 degrees
Possible measurements for angle c :=
99 =< c <= 103 (answer).