# Math

posted by Johnny

o is the center of the regular pentagon ABCDE. How many degrees are there in OAB?

Please explain or show work

A.36
B.54
C.72
D.108
E.126

1. Steve

divide 360 into 5 equal parts. What do you get? 72.

But, that is angle AOB, the vertex of an isosceles triangle. So, each of the base angles (OAB and OBA) is (180-72)/2 = 54.

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