Answer:
a = 21°
b = 70°
c = 89°
Step-by-step explanation:
angle of measure b and the angle of measure 110 are two supplementary angles
Then b + 110 = 180
Therefore b = 180 - 110 = 70°
angle of measure b and the angle of measure 21 are two opposite angles
Then a = 21
We Know that the sum of the interior angles of a triangle equal to 180
Then a + b + c = 180
Therefore c = 180 - a - b = 180 - 21 - 70 = 159 - 70 = 89°
