In the diagram, PQR is a triangle.|PQ| = |PR|, |PS| = |SQ| and PRS = 50°. What is the size of ∠PSQ?
A.
75o
B.
80o
C.
85o
D.
95o
Correct answer is B
< PQS = 50° (PQ = PR)
< PQS = < SPQ = 50° (QS = PS)
In triangle PSQ, < PQS + < QPS + < PSQ = 180°
50° + 50° + < PSQ = 180°
< PSQ = 180° - 100° = 80°