(i) ∠A + ∠B + ∠C = 180°
x° + 50° + 60° = 180°
(By Angle sum property of a triangle)
∠x + 110° = 180°
∠x = 180° – 110°
∠x = 70°
(ii) ∠P + ∠Q + ∠R = 180°
90° + 30° + ∠x = 180°
(By Angle sum property of a triangle)
120° + ∠x = 180°
∠x = 180° – 120° = 60°
(iii) ∠X + ∠Y + ∠Z = 180°
30° + 110° + ∠x = 180°
(By Angle sum property of a triangle)
140° + ∠x = 180°
∴ ∠x = 180° – 140° = 40°
(iv) 50° + x + x = 180°
50° + 2x = 180°
(By Angle sum property of a triangle)
2x = 180° – 50° = 130°
x = \(\frac{180^o}{2}\)
∴ ∠x = 60°
(v) x + x + x = 180°
(By Angle sum property of a triangle)
3x = 180°
x = \(\frac{180^o}{2}\)
∴ x = 60°
(vi) x + 2x + 90° = 180°
(ByAngle sum property of a triangle)
3x = 180°
x = \(\frac{180^o}{3} = 60^o\)