Supplementary angles add up to 180 degrees
Complementary angles add up to 90 degrees
So if angle 2 is x
Then angle 1 is x - 28
And we can set up the equation
x + (x-28) = 180
2x - 28 = 180
2x = 208
x = 104
And then the second equation is:
Angle 1 + Angle 3 = 90
Angle 1 = 104 - 28 = 76
76 + Angle 3 = 90
Angle 3 = 14
So the angles are, again:
∠1 = 76
∠2 = 104
∠3 = 14