In the diagram, POS and ROT are straight lines, OPQR is a parallelogram. |OS| = |OT| and ∠OST = 50°. Calculate ∠OPQ.
-
A.
160o -
B.
140o -
C.
120o -
D.
100o
Correct Answer: Option D
Explanation
< T = < S = 50° (OS = OT)
< SOT = 180° – 2(50°) = 80°
< ROP = 80° (vertically opposite angle)
(therefore) < OPQ = 180° – 80° = 100° (adjacent angles)