In the diagram, POS and ROT are straight lines. OPQR is a parallelogram, |OS| = |OT| and ∠OST = 50°. Calculate the value of ∠OPQ.
100\(^o\)
120\(^o\)
140\(^o\)
160\(^o\)
Correct answer is A
S\(O\)T = 180\(^o\) - (50 + 50)
= 80\(^o\)
P\(Q\)R = 80\(^o\)
= \(\frac{360^o - 160^o}{2}\) = 100\(^o\)