(i) ∠x + 50° = 115°
∵ The exterior angle of a triangle is equal to the
sum of its two interior opposite angles.
∵ ∠x = 115° – 50° = 65°
(ii) ∠x + 70° = 100°
(∵ The exterior angle of a triangle is equal to the sum of its two interior opposite angles)
∴ ∠x = 100° – 70°= 30°
(iii) ∠x + 90° = 125°
∵ The exterior angle of a triangle is equal to the sum of its two interior opposite angles.
∴ ∠x = 125° – 90° = 35°
(iv) ∠x + 60° = 120°
∵ The exterior angle of a triangle is equal to the sum of its two interior opposite angles.
∠x = 120° – 60° = 6o°
(v) ∠x + 30° = 80°
∵ The exterior angle of a triangle is equal to the sum of its two interior opposite angles.
∵ ∠x = 80° – 30° = 50°
(vi) ∠x + 35° = 75°
∵ The exterior angle of a triangle is equal to the sum of its two interior opposite angles.
∴ ∠x = 75° – 35° = 40°