Answer:
C. 55
Step-by-step explanation:
Since all angles in a triangle add up to 180°, we have:
40 + y + y + 30 = 180
2y + 70 = 180
2y = 110
y = 55
C. 55º
A triangle is 180º.
So, 40+y+30+y = 180º Form an equation to solve it. Then combine like terms
70+2y = 180º Subtract 70 on both sides.
2y = 110º Divide 2 on both sides
y = 55º The answer is 55º
