In the diagram above, |PQ| = |QR|, |PS| = |RS|, ∠PSR = 30o and ∠PQR = 80o. Find ∠SPQ.
Attached Figure / Diagram
A
15o
B
25o
C
40o
D
50o
E
55o
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
Join PR
QRP = QPR
= 180 - 80 = \(\frac{100}{20}\) = 50º
SRP = SPR
= 180 - 30 = \(\frac{150}{2}\) = 75º
∴ SPQ = SPR - QPR
= 75 - 50 = 25º
Source: Myschool Past Questions Archive (Record #23208)