Mathematics

The triangle PQR above is

The triangle PQR above is
  • A.
    an obtuse-angled triangle
  • B.
    a scalene triangle
  • C.
    an isosceles triangle
  • D.
    an equilateral triangle
Correct Answer: Option C
Explanation

∠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