Answer:
c = 29°
Step-by-step explanation:
the sum of the 3 angles in a triangle = 180°
sum the 3 angles and equate to 180
2c - 6 + c + 12 + 3c = 180 , that is
6c + 6 = 180 ( subtract 6 from both sides )
6c = 174 ( divide both sides by 6 )
c = 29
