Iwill award 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.

In the given figure:

The reflex angle and

 [By vertical angle theorem]

From the given we can say that:

and are supplementary angles.

Supplementary angles states that the two measure are add up to 180 degree.

⇒          .....[1]

then; the reflex angle DOB is:

Substitute the given values we get;

Subtract y from both sides we get;

Divide both sides by 2.5 we get;

We have to find the non reflex

Non reflex angle DOB is;

Therefore, the non-reflex angle DOB is 108 degree.

2x^2+5x+17

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