In the diagram, POR is a circle with center O. ∠QPR = 50^\circ, ∠PQO = 30^\circ and ∠ORP = m. Find m.
Attached Figure / Diagram
A
20o
B
25o
C
30o
D
50o
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
< QOR = 50^\circ x 2 = 100^\circ
Reflex < QOR = 360^\circ - 100^\circ = 260^\circ
\(\therefore\) 30^\circ + 50^\circ + 260^\circ + m = (4 - 2) x 180^\circ
340^\circ + m = 360^\circ
m = 360^\circ - 340^\circ = 20^\circ
Source: Myschool Past Questions Archive (Record #26392)