A regular square is inscribed in a circle. If A and B are adjacent vertices of the pentagon and O is the center of the circle, what is the value of ∠OAB ? Choose the most appropriate option:
A) 45 degrees
B) 54 degrees
C) 72 degrees
D) 84 degrees
E) 108 degrees
its a regular square so divide the globe by 4.   = 360/4= 
<gadget id="calculator">360/4</gadget>
<output>90</output>
90   90 would be the angle at O.   Angles at A and B are equivalent, so   90 + 2x= 180   2x = 90   x =45   Angles OAB and OBA will be 45 degrees each.   45 degrees
<result>A</result>
A regular square is inscribed in a circle. If A and B are adjacent vertices of the pentagon and O is the center of the circle, what is the value of ∠OAB ?