The triangle PQR above is
Attached Figure / Diagram
A
an obtuse-angled triangle
B
a scalene triangle
C
an isosceles triangle
D
an equilateral triangle
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
∠PQR = 180 - 128 (∠s on a straight line)
= 52o
∠QPR + 76 + 52 = 180(extr ∠ = sum of intr. opp ∠s)
∠QPR + 128 = 180
∠QPR = 180 - 128
= 52o
∴ΔPQR is an isosceles triangle
Source: Myschool Past Questions Archive (Record #10930)