The options are;
A) b + c = 90
B) 90 + c = 180
C) b + c = 180
D) 42 + b = 150
Answer:
C) b + c = 180
Explanation:
From angle theorems, we know that sum of angles on a straight line is 180°
Now, c and 42° form a straight line.
Thus;
c + 42 = 180°
c = 180 - 42
c = 138°
Similarly b and c form a straight line and so;
b + c = 180°
From the given options, the only correct one is Option C.