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 answers: A) 48 degrees B) 54 degrees C) 72 degrees D) 84 degrees E) 72 degrees

Rationale: its a regular 10 sided so divide the globe by 10 . = 360 / 10 = 36 36 would be the angle at o . angles at a and b are equivalent , so 36 + 2 x = 180 2 x = 144 x = 72 angles oab and oba will be 72 degrees each . e
Answer: E