In the diagram, PR is a diameter of the circle PQRS. PST and QRT are straight lines. Find QRS
Attached Figure / Diagram
A
20o
B
25o
C
30o
D
35o
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
o) = 90o (angle substended by a semi-circle)
∴ o
o - 30o = 60o
o - 35o = 55o
o + 55o) = 180 - 115o = 65o
o(angles in the same segment)
o
o + 35o = 180o
o
o - 155o
= 25o
Source: Myschool Past Questions Archive (Record #33076)