In the diagram above, AB, CD and XY are straight lines intersecting at W. Find ∠CWX
A.
20o
B.
80o
C.
100o
D.
120o
E.
140o
Correct answer is B
a = 40o (vertical opp. ∠s are equal) b = 60o
a + b + c = 180o (sum of ∠s on a str line)
40o + 60o + c = 180o
C = 180o - 100o
C = 80o