Answer:
1. a = 21°
2. b = 70°
3. c = 89°
Explanation:
1. Determination of the value of a.
a = 21° (vertically opposite angles are equal)
2. Determination of the value of b.
From the question given above,
110 + b = 180 (sum of angles on a straight line)
Collect like terms
b = 180 – 110
b = 70°
3. Determination of the value of c.
a + b + c = 180 (sum of angles in a triangle)
a = 21°
b = 70°
c =?
21 + 70 + c = 180
91 + c = 180
Collect like terms
c = 180 – 91
c = 89°