1. We know that Sum of Three Angles in a Triangle is 180
⇒ m∠1 + 75 + 40 = 180
Option B is the Answer
2. We know that Sum of Three Angles in a Triangle is 180
⇒ ∠1 + 30 + 20 = 180
⇒ ∠1 + 50 = 180
⇒ ∠1 = 180 - 50
⇒∠1 = 130
3. We know that Sum of Three Angles in a Triangle is 180
⇒ ∠1 + 75 + 35 = 180
⇒ ∠1 + 110 = 180
⇒ ∠1 = 180 - 110
⇒ ∠1 = 70
4. We know that Sum of Three Angles in a Triangle is 180
⇒ ∠1 + 60 + 60 = 180
⇒ ∠1 + 120 = 180
⇒ ∠1 = 180 - 120
⇒ ∠1 = 60
5. We know that Sum of Three Angles in a Triangle is 180
We can notice that the Given Triangle is a Right Angled Triangle
We know that One Angle in Right Angled Triangle is 90
⇒ ∠2 + 90 + 30 = 180
⇒ ∠2 + 120 = 180
⇒ ∠2 = 180 - 120
⇒ ∠2 = 60
6. We know that Sum of Three Angles in a Triangle is 180
We can notice that the Given Triangle is a Right Angled Triangle
We know that One Angle in Right Angled Triangle is 90
⇒ ∠2 + 90 + 40 = 180
⇒ ∠2 + 130 = 180
⇒ ∠2 = 180 - 130
⇒ ∠2 = 50
7. We know that Sum of Three Angles in a Triangle is 180
We can notice that the Given Triangle is a Right Angled Triangle
We know that One Angle in Right Angled Triangle is 90
⇒ ∠2 + 90 + 45 = 180
⇒ ∠2 + 135 = 180
⇒ ∠2 = 180 - 135
⇒ ∠2 = 45
8. We know that the Exterior Angle of one Vertex of a Triangle is the Sum of Other two vertices interior angles.
⇒ ∠3 = 80 + 60
⇒ ∠3 = 140
9. We know that the Exterior Angle of one Vertex of a Triangle is the Sum of Other two vertices interior angles.
⇒ ∠3 = 40 + 35
⇒ ∠3 = 75
10. We know that the Exterior Angle of one Vertex of a Triangle is the Sum of Other two vertices interior angles.
⇒ ∠3 = 75 + 65
⇒ ∠3 = 140
11. We know that Sum of Three Angles in a Triangle is 180
⇒ x + x + 108 = 180
⇒ 2x + 108 = 180
⇒ 2x = 180 - 108
⇒ 2x = 72
⇒ x = 36
12. We know that Sum of Three Angles in a Triangle is 180
⇒ 60 + 60 + 3x = 180
⇒ 3x + 120 = 180
⇒ 3x = 180 - 120
⇒ 3x = 60
⇒ x = 20
13. We know that Sum of Three Angles in a Triangle is 180
We can notice that the Given Triangle is a Right Angled Triangle
We know that One Angle in Right Angled Triangle is 90
⇒ (5x + 3) + 47 + 90 = 180
⇒ 5x + 140 = 180
⇒ 5x = 180 - 140
⇒ 5x = 40
⇒ x = 8
14. We can notice that the Given Diagram is a Right angled Triangle :
⇒ ∠1 + 90 + 45 = 180
⇒ ∠1 + 135 = 180
⇒ ∠1 = 180 - 135
⇒ ∠1 = 45