Answer:
252°
Step-by-step explanation:
In the figure attached, the diagram is shown. There, we can see that
∠DOB = ∠AOD + ∠AOC + ∠COB
Replacing with the equivalences: ∠DOB has a measure of 3.5y, the measure of ∠AOD is y, and ∠AOC + ∠COB measure 180°, we get:
3.5y = y + 180°
3.5y - y = 180°
2.5y = 180°
y = 180°/2.5
y = 72°
Therefore, ∠DOB = 3.5*72° = 252°
