EXERCISE 6.2
1) Find the value of the unknown exterior angle x in the following diagram:
i) ∠x = 50ᵒ + 70ᵒ —- (exterior angle property)
∠x = 120ᵒ
ii) ∠x = 65ᵒ + 45ᵒ —– (exterior angle property)
∠x = 110ᵒ
iii) ∠x = 30ᵒ + 40ᵒ —— (exterior angle property)
∠x = 70ᵒ
iv) ∠x = 60ᵒ + 60ᵒ ——- (exterior angle property)
∠x = 120ᵒ
v) ∠x = 50ᵒ + 50ᵒ (exterior angle property)
∠x = 100ᵒ
vi) ∠x = 60ᵒ + 30ᵒ —– (exterior angle property)
∠x = 90ᵒ
2) Find the value of the unknown interior angle x in the following figures:
Ans:
i) Sum of interior opposite angles = Exterior angle
x + 50ᵒ = 115ᵒ
x = 115ᵒ – 50ᵒ
x = 65ᵒ
ii) Sum of interior opposite angles = Exterior angle
x + 70ᵒ = 100ᵒ
x = 100ᵒ – 70ᵒ
x = 30ᵒ
iii) Sum of interior opposite angles = Exterior angle
x + 90ᵒ = 125ᵒ
x = 125ᵒ – 90ᵒ
x = 35ᵒ
iv) Sum of interior opposite angles = Exterior angle
x + 60ᵒ = 120ᵒ
x = 120ᵒ – 60ᵒ
x = 60ᵒ
v) Sum of interior opposite angles = Exterior angle
x + 30ᵒ = 80ᵒ
x = 80ᵒ – 30ᵒ
x = 50ᵒ
vi) Sum of interior opposite angles = Exterior angle
x + 35ᵒ = 75ᵒ
x = 75ᵒ – 35ᵒ
x = 40ᵒ