Complementary angles are angles that add up to 90 degrees. Supplementary angles are angles that add up to 180 degrees.
So therefore we know that A and B always add up to 90 degrees and B and C always add up to 180 degrees.
So first question:
A + B = 90
52 + B = 90
-52 -52
B = 38
And then B + C = 180
38 + C = 180
-38 -38
C = 142
You can do the same thing for the second problem, except this time you already know B.
A + 67 = 90
-67 -67
A = 23
67 + C = 180
-67 -67
C = 113
Next one:
Now you have to first find the angle of B.
B + 107 = 180
-107 -107
B = 73
A + 73 = 90
-73 -73
A = 17
Last one:
A + 12 = 90
-12 -12
A = 78
12 + C = 180
-12 -12
C = 168
