(SAT Prep) In the given figure, the reflex angle ∠DOB has measure of 3.5y while the measure of ∠AOD is y. Find the measure of the non-reflex ∠DOB in degrees.

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°