A regular 10 sided area 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 correct choice from the following options:
A) 48 degrees  B) 54 degrees  C) 72 degrees  D) 84 degrees  E) 72 degrees
its a regular 10 sided so divide the globe by 10.   = 360/10= 
<gadget id="calculator">360/10</gadget>
<output>36</output>
36   36 would be the angle at O.   Angles at A and B are equivalent, so   36 + 2x= 180   2x = 144   x = 72   Angles OAB and OBA will be 72 degrees each.   72 degrees
<result>E</result>
A regular 10 sided area 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 ?