In the diagram, PQRS is a circle center O. PQR is a diameter and ∠PRQ = 40^\circ. Calculate ∠QSR.
Attached Figure / Diagram
A
30o
B
40o
C
45o
D
50o
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
< Q = < R (OQ = OR = radii)
< QOR = 180^\circ - 2(40^\circ) = 100^\circ
< QSR = < RPQ = \(\frac{1}{2}\) < QOR
= \(\frac{100}{2} = 50^\circ\)
Source: Myschool Past Questions Archive (Record #26446)